That's all from us tonight, but we'll be back tomorrow with more drama from the London Stadium.

Here's how day four's evening session unfolded:

• Britain win two golds and two bronze medals, to add to earlier gold from Olivia Breen in long jump T38.
• Hannah Cockroft takes second win of Championships in women's 800m T34 ahead of compatriot Kare Adenegan in third.
• GB's Sophie Kamlish wins 100m T44 final after setting world record in heats.
• Fellow Brit Richard Whitehead wins bronze in 100m T42 final
• America top the medal table after wins for Tatyana McFadden and Michael Brannigan in track events.

Image source, Getty Images

Richard Whitehead was asked about the future of his event on BBC Radio 5live.

The British bronze medallist gave this empassioned speech: "There isn't a 100m event in Tokyo [Paralympics], there's only 200m for myself and Dave Henson. That's because the IPC are trying to shrink the programme. For me it's about performance, inclusion, and offering opportunities for performance, not actually restricting the programme.

"It's a backwards step for the IPC. Hopefully they will do a u-turn on that decision - especially after today."

Image source, Getty Images

Britain's Richard Chiassaro speaks to BBC Radio 5 live after crashing in the T54 50m final: "Marcel Hug came into my lane a little bit, we touched and I flipped. My finger looks broken maybe. I might get it checked.

"The plan in the race was to stick with Marcel if he went into the lead and try to follow him."

Remarkably, Chiassaro was able to get back on the track and ended up finishing in fifth place.

Image source, .

That's it - the final race of day four is done and British pair Ben Rowlings and Issac Towers have to settle for fifth and seventh place respectively.

Tunisian Walid Ktila takes gold in 50.56.

Last but by no means least, Ben Rowlings and Isaac Towers go in the final race of day four - the men's 400m T34 final.

Rowlings picked up bronze in this event at the European Championships last year and finished just behind team-mate Towers, who collected silver.

Towers also took home Euro gold in the 800m - one of five individual medals he collected.

Baroness Tanni Grey-Thompson
11-time Paralympic champion

It's just one of those things. It doesn't happen very often. Sometimes you get track rash and grazes but at this speed when you're so close, you can be a centimetre off their back bar. The slightest touch you can be out and you can't jump out the way.

Chris Osborne
BBC Sport at London Stadium

A huge groan goes around the stadium as they watch the horrible collision.

Richard Chiassaro is upright and wheeling around to the home straight now.

A very strange ending to this race, but the Paralympic champion comes out with the gold medal.

Marcel Hug finishes first in 1:37.64, ahead of Yang Liu of China and Saichon Konjen of Thailand.

Image source, Rex Features

Baroness Tanni Grey-Thompson
11-time Paralympic champion

They're doing 23 or 24 mph. Richard's compensator which guides you around the bend, he's hit it twice and it's cost him around the bend. You have to hit it cleanly to get you around the bend.

Ouch!published at 21:36 British Summer Time 17 July 2017

21:36 BST 17 July 2017

Men's 800m T54 final

Oh my...a huge collision in this race.

Richard Chiassaro falls from his chair and takes out around three or four other riders as they come into the home straight.

Marcel Hug is out in front of a close-knit group, and Briton Richard Chiassaro is right in there on the inside.

You might recognise the name Marcel Hug in this race.

Hug is a long-time rival of Britain's David Weir. They've enjoyed many a battle over the years and the Paralympic champion goes in lane five.

The Swiss athlete is the world record holder in this category.

There are still three more British athletes left to compete tonight - and the next one is up in the men's 800m T54 final at 21:31 BST.

Richard Chiassaro were part of the victorious 4x400m relay team at the European Championships last year.

Chiassaro, 35, who has spina bifida, also picked up four individual medals at the same event - including silver in the 800m.

Image source, Getty Images

Chris Osborne
BBC Sport at London Stadium

Image source, .

I was given a bit of behind the scenes access to what they call the F1 pit stop here at London Stadium.

With so many wheelchairs, blades, prosthetics and throwing seats, it's inevitable that some of it will need a tune up at some point.

And that's where these guys come in.

British T42 long jumper Luke Sinnott (pictured above) said he had felt a clicking in the joint of hid blades. So he was in the tent with his legs off, getting them re-aligned and sand removed from the joint.

Sand is an occupational hazard of the long jumper.

There's 24 staff, working across two shifts, sewing machines, solder irons and even hot ovens to keep the para-athletes - and their kit - in working condition.

Image source, .

Chris Osborne
BBC Sport at London Stadium

Image source, .

Throughout that T20 1500m there was a high-pitched screech coming from over my left shoulder.

Turns out it was a relation of Steve Morris who put as much welly into her cheering as the British pair put into their running on the track.

James Hamilton goes over with Morris to see some friends and family,

Image source, ,

American Tatyana McFadden after winning her second gold of the day, speaking to BBC Radio 5 live: "It was a really good race. My style was kind of rough but I knew I could make it up in the transition. It's perfect weather to race.

"I was exhausted coming in. I tried to take a little nap and do some therapy on my legs and try to stay relaxed. In training we train twice a day and it's in preparation for days like today."

Image source, PA

Michael Brannigan comes home way ahead of the pack to take gold. The American, who has autism, is the world record holder in this event.

Image source, PA

Steve Morris of GB was looking good but fell off the pace during the last lap and had to settle for fourth, with his compatriot James Hamilton coming in sixth.

Next up is the men's 1500m T20 final, featuring Steve Morris and James Hamilton from Britain.

Both Welshman Morris and Northern Ireland's Hamilton, who have intellectual impairments, are looking for their first major titles.