The memorial service is now under way inside St Paul's Cathedral.

Let's bring you some of the latest images which have come to us in the last few moments.

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

London falls silent with only the sound of the bells of St Paul's Cathedral echoing across the capital.

The tolling bells signal the start of the memorial service.

A reminder, you can watch live to coverage by clicking Play at the top of this page.

Image source, Various

The youngest of the bombers, Hasib Hussain, detonated his device on a double-decker bus in Tavistock Square, not far from King's Cross.

The bombing, the fourth and final attack, took place at 09:47 BST - about an hour after the other explosions.

The number 30 bus was torn apart in front of the headquarters of the British Medical Association, where a conference was being held. While medical equipment was lacking, dozens of doctors offered lifesaving expertise.

Thirteen people who were on the bus were killed. They were:

• Anthony Fatayi-Williams
• Jamie Gordon
• Giles Hart
• Marie Hartley
• Miriam Hyman
• Shahara Islam
• Neetu Jain

• Sam Ly
• Shyanuja Parathasangary
• Anat Rosenberg
• Philip Russell
• William Wise
• Gladys Wundowa

Click on their names to read their stories.

Image source, Various

The most deadly attack occurred on the Piccadilly Line between King's Cross and Russell Square.

Germaine Lindsay detonated his bomb next to the rear set of double doors in the front carriage of the packed train, just after it pulled out of King's Cross station at 08:49.

Twenty-six people were killed. The victims were:

• James Adams
• Samantha Badham
• Philip Beer
• Anna Brandt
• Ciaran Cassidy
• Rachelle Chung For Yuen
• Elizabeth Daplyn
• Arthur Frederick
• Karolina Gluck
• Gamze Gunoral
• Lee Harris
• Ojara Ikeagwu
• Emily Jenkins
• Helen Jones
• Susan Levy
• Shelley Mather
• Michael Matsushita
• James Mayes
• Behnaz Mozakka
• Mihaela Otto
• Atique Sharifi
• Ihab Slimane
• Christian Small
• Monika Suchocka
• Mala Trivedi
• Adrian Johnson

Click on their names to read their stories.

Image source, Various

Shehzad Tanweer detonated his device on an eastbound Circle Line train between Liverpool Street and Aldgate at 08:49.

The explosion at the rear of the second carriage killed seven people.

The victims were:

• Lee Baisden

• Benedetta Ciaccia

• Richard Ellery
• Richard Gray
• Anne Moffat
• Carrie Taylor
• Fiona Stevenson

Click on their names to read their stories.

Image source, Various

Ahead of the service we'll take a moment to remember those who died in the attacks.

Three of the four bombs went off just before 08:50 BST on Tube trains that had departed King's Cross.

Ringleader Mohammad Sidique Khan detonated his device on a westbound Circle Line train heading towards Paddington.

The bomb exploded at Edgware Road in the second carriage close to the second set of double doors. It killed six people.

The victims were:

• Michael Stanley Brewster
• Jonathan Downey
• David Graham Foulkes
• Colin William Morley
• Jennifer Vanda Nicholson
• Laura Webb

Click on their names to read their stories.

Anna O'Neill
BBC London, reporting from St Paul's Cathedral

This it the scene from St Paul’s where people have started to arrive for the commemorative service which will be starting shortly.

Seen arriving at the church were members of the emergency services including assistant commissioner of London Fire Brigade, Patrick Gouldbourne, Dawn Butler MP, as well as some of the survivors of the attacks and their families.

Image source, Reuters

Events have been taking place this morning to mark the 20th anniversary of the 7/7 bombings that rocked central London, left 52 people dead and injured more than 700.

Here is what has taken place so far:

• The King called on the nation to remember the "extraordinary courage and compassion" in the face of the horrors of the 7 July bombings
• A minute's silence was held at 8:49 at three London Underground stations to mark the moment the bombs on the Tube trains were detonated
• Tavistock Square hosted a further minute's silence at about 9:47 to mark the time of the fourth and final blast on the number 30 bus
• Prime Minister Sir Keir Starmer joined the mayor of London at a wreath laying ceremony at the 7 July Memorial in Hyde Park
• Those injured in the attacks and those who lost loved ones are continuing to share their memories of that day

The Duke and Duchess of Edinburgh will join political leaders in attending the National Service of Commemoration at St Paul's Cathedral which starts at 11:30.

Aisling Taylor
Reporting from St Paul's Cathedral

People are arriving at St Paul's Cathedral where the main memorial service is due to start at 11:30.

Representatives of Transport for London and the emergency services are lining the steps of the cathedral.

The service will be attended by survivors and families of the victims, as well as the prime minister and other leading politicians.

The Duke and Duchess of Edinburgh are expected to arrive shortly before the service begins.

Karl Mercer
Political editor, BBC London

Craig Cassidy, who has been a paramedic with the London Ambulance Service since 1999, says seeing fatally injured people in the tunnel in Aldgate following the 7/7 bombings is seared into his memory.

"You cannot prepare for this kind of thing," he says. "You do what's in front of you, you deal with what you're presented with, knowing that you've never experienced this before, but you've got to get on with it.

"I put myself to one side. When I when I'm at work, I'm not Craig. I put my uniform on, I'm a different person, I'm a paramedic."

Reflecting on his involvement on the day, he adds: "I hope I did it well. I hope I gave some comfort to some of the people. I hope they realised that they weren't alone at that point.

"I've been back to that station many times because I still work in the same area. When I go back in, it's still present with me.

"Every one of them was someone's partner, someone's wife, someone's husband, someone's son. Parents should never bury a child, and I knew that was going to be happening."

Sir Sadiq Khan has been speaking to the BBC ahead of the commemoration event at St Paul's Cathedral.

The London mayor says he remembers the day of the bombings "vividly" and how he began calling around his family to check they were safe.

“Most of us use the Tube, most of us use the buses. None of us knew whether our family and loved ones were safe. None of us knew if there’d be further attacks that day," he says.

"What we did see were remarkable signs of kindness and bravery," the mayor adds.

Sir Sadiq praised the emergency services and transport workers who ran towards danger during the attacks, as well as civilians who acted as "guardian angels".

“That’s who we are and that’s what London is all about.

“What these terrorists hate is our diversity, our way of life.

Image source, PA Media

Kemi Badenoch is the latest political leader to pay tribute to the 52 victims and hundreds injured in the 7/7 attacks.

"Today, we stand with those who carry the pain of that day, the families, friends and colleagues of those who never came home," the Conservative leader says.

"We will remember them always."

The brother of a woman killed on 7/7 says he cannot forgive those behind the bomb attacks, two decades on.

On 7 July 2005, 29-year-old Laura Webb was on her way to work in central London when she was killed – one of 52 people who died in co-ordinated attacks on the city.

Rob Webb, Laura's older brother, says 7/7 was "an attack on all of us" and should never be forgotten.

"I remain angry," says Rob, who lives near Cardiff.

"Laura was denied the opportunity of a life that me and my brother have been lucky enough to have - somebody decided to take that away from her.

"The pain never goes away - I think of her every day."

Read their story here.

James W Kelly
BBC London

As memorial events continue, those who were on the Tube that day continue to share their memories.

Sajda Mughal was among the passengers on the Piccadilly line train that left King's Cross.

“I was running late that morning so that should not have been my Tube," she tells BBC Radio 5 Live.

“The Tube leaves King's Cross and it was only 10 seconds into the tunnel, towards Russell Square, it was a massive bang and the train shook as if there’d been an earthquake and it came to a sudden halt."

She says the "screams just went on" after what she initially thought was a train derailment. "I never thought it was a bomb."

“My life changed 360 degrees. I went from working in the corporate world - in my early 20s it was my dream to be in London - and then I started working at the grassroots because I wanted to change hearts and minds so that it wouldn’t happen again."

Image source, PA Media

We hear now from Home Secretary Yvette Cooper, the cabinet minister in charge of counter-terrorism, who says the UK will "always confront the threats facing this country".

"Twenty years have passed since 7/7 but the passage of time makes what happened that day no less shocking. It was an appalling attack on our capital city and on democracy itself," she says.

"Amid the horror of that day, we saw the best of people, our emergency services, first responders and ordinary Londoners who bravely acted to help one another."

Aisling Taylor
Reporting from Tavistock Square

At Tavistock Square British Medical Association (BMA) staff members have been laying flowers under the memorial plaque in front of the BMA building.

Some staff members were visibly emotional as they paused to reflect on the events 20 years ago.

This is where the fourth and final device detonated on a bus killing 13 passengers onboard.

After the blast, doctors inside the BMA building rushed out to help those on the street in front of them.

Dominic Casciani
Home and Legal Correspondent

Image source, Tony Woolliscroft/Mirror Books

Despite 20 years passing since the 7/7 attack, for Dan Biddle the emotional scarring is as constant a reminder as the physical trauma he was left with that day.

The face of the lead suicide bomber, Mohammad Sidique Khan, has never left his memory.

"I can be in the kitchen and he is stood in the garden," says Dan, who has complex post-traumatic stress disorder.

"He's there, dressed as he was on the day, holding the rucksack, just with his hand above it, about to detonate it again."

Even if Dan looks away, the bomber is still there when he looks back.

"I saw this guy literally disassemble himself in front of me, and now I'm seeing him again."

Read Dan's story here.

Alpa Patel
BBC London

Last month I spoke to Steven Desborough who was aged 27 when he was travelling in the Circle line train that was bombed outside Aldgate.

He was the last surviving civilian to leave the Tube following the attack and described how he heard a loud bang and a screech, before there was a big white flash.

Following the explosion he tried to help others on the train by trying to reassure people to stop them going into shock and held a young lady in his arms, who later passed away.

"I don't feel I did anything out of the ordinary," he said. "I did what I could, but I wish I could have done more. I did my best on the day."

Image source, Steven Desborough

Reflecting on what happened 20 years on, he said it "changed me for the better".

"It's made me more patient, more empathetic. But it hasn't defined me."

You can read more about Steven's story and how he has coped following the attack here.

The 7/7 suicide bombings took place at locations across central London's transport network.

Three of the attacks took place on the London Underground at 8:49 while the fourth was at Tavistock Square an hour later on the number 30 bus.

Harry Low
BBC London, reporting from Tavistock Square

Sir Keir Starmer joined victims' families, personnel from the emergency services and others at Tavistock Square to mark the minute's silence.

He laid a wreath to remember the 13 people who died on the number 30 bus in what would be the final bomb attack of the day.

It's a sombre mood inside the park where the victims are being remembered.