Harrison has been flying under the radar this week behind Hickman and Dunlop.

Don't forget, he is a previous winner of this race and you can't write him off!

He's cleared Davo Johnson on the road and has clear track in front of him.

1. Harrison Leader

2. Hickman +0.503

3. Dunlop +2.267

4. Hillier + 2.2795

5. Cummins + 0.638

6. Todd +1.1.148

Dean Harrison is right on the back wheel of Davo Johnson through Glen Helen.

He's the fastest man through...and ahead of Dunlop! Dunlop is 2.7 down on Harrison.

Here comes Hickman....and Harrison is faster still! What a start for the DAO Racing man!

Richard Petrie
BBC Sport at the Isle of Man TT

There are some mighty sweet sounds filling the air as the bikes leave the start line and head off towards St Ninian's crossroads.

Among them the exotic £250,000 MotoGP-based RCV Honda piloted by Michael Rutter and the R1 Yamaha being ridden by James Hillier.

Both are complemented by very attractive looking livery, a feast of colour.

A treat for all the senses this....the pulses are racing and the adrenaline flowing around the grandstand.

Davo Johnson gets the famous tap on the shoulder and he blasts down towards Bray Hill.

Dean Harrison, who you can't write off, is next away, swiftly followed by the legendary John McGuinness, Jamie Coward and James Hillier.

Michael Dunlop is the sixth man away, with Josh Brookes and Davey Todd in pursuit.

And here goes Hickman, the fastest road racer in history.

The first timing beam is at Glen Helen, and we'll bring you updates as they happen!

Six laps, here we go!

Michael Dunlop and Peter Hickman have been the star men at the Isle of Man TT and today's Senior TT has been billed as a duel between the two riders.

Here's how they stack up after a week of practice and racing.

The Isle of Man TT is a time trial race, so the aim is to complete six laps as quickly as possible.

Riders set off from the start at 10-second intervals and are racing the clock - and themselves.

Overtaking is possible if you catch the riders in front, something you can expect to see from Dean Harrison, Michael Dunlop and Peter Hickman.

Time can be made up or lost depending on how quickly you can get past slower riders.

There will be two pit stops for fuel over the six-lap race, and again this can be crucial come the final results.

The winner is the one who completes the six laps the fastest. Unlike MotoGP or Formula 1 this isn't necessarily the first rider over the line due to the staggered start, but we'll keep you up to date on who is where when we get to the crucial

Image source, Pacemaker

Despite the rumours of Hickman using his record-breaking Superstock, it looks like he will use his FHO BMW Superbike for the Senior TT.

Who would bet against him going even quicker- this afternoon?

Richard Petrie
BBC Sport at the Isle of Man TT

The Isle of Man TT is an event steeped in history and heritage with the names of heroes past and present being revered and readily tripping off the tongue of generations of fans.

Geoff Duke, Mike Hailwood, Giacomo Agostini, Joey Dunlop, John McGuinness and more recently, Michael Dunlop and Peter Hickman.

Today Michael stands on the threshold of motorcycling greatness as he aims to equal the tally achieved by his uncle, the late Joey Dunlop.

Can he reach that goal or must he wait another 12 months for another chance? We will know the answer to that question in around another two hours.

I'll not repeat the word used when Peter Hickman crossed the line to record his record-breaking lap in yesterday's Superstock race. Let's just say it was impressive.

In theory, Superstock bikes are the second-quickest machines behind the Superbikes, which are set to run in today's Senior TT.

However, you can run a Superstock bike in a Superbike race, so it will be interesting to see if Hickman opts to run with his record-breaking machine instead of the Superbike.

Richard Petrie
BBC Sport at the Isle of Man TT

Conditions are perfect and the riders and bikes are heading out onto the grid, onto the most famous piece of tarmac in international road racing, on Glencrutchery Road.

There is a heady mix of excitement, nerves, tension and anticipation in the air, unlike that experienced before any other race. The extent of the challenge that awaits ensures that.

In the race paddock, mechanics have been meticulously making last-minute checks on machine preparation in a sport where attention to detail is not only critical to performance and result, but also to the rider's very survival.

Merchandise suppliers and food and drink stalls have been doing a roaring trade behind the grandstand for the entire fortnight and the bikes have been through scrutineering for all the necessary checks that they are fit for the rigours of 226 miles of high speed road racing.

It's almost time....

The top 20 riders are seeded and set off in the order. We've highlighted those to keep an eye out, and could be in podium contention, in bold.

1. Davo Johnson

2. Dean Harrison

3. John McGuinness

4. Jamie Coward

5. James Hillier

6. Michael Dunlop

7. Josh Brookes

8. Davey Todd

10. Peter Hickman

11. Conor Cummins

12. Michael Rutter

Richard Petrie
BBC Sport at the Isle of Man TT

The Senior TT is the culmination of a fortnight of practice and racing over the closed public roads which form the 37.73-mile Mountain Course.

It is the biggest event of the year in the international road racing calendar, an occasion which brings a special buzz and there is a palpable sense of anticipation ahead of the blue riband event of the meeting.

After the sensational record-breaking action which we have witnessed throughout the two weeks the atmosphere is electric, rife with expectation of a thrilling showdown between the two men who have dominated the event so far, Peter Hickman and Michael Dunlop.

For most of the riders taking part it is their most important race of the year - a unique annual experience of 226 miles of pure road racing at its very rawest, with all the attendant dangers that brings.

Reaching maximum speeds of up to 200mph between lamp-posts, stone walls, hedges, trees and all the other 'furniture' associated with public roads.

For the remainder of the year, bar the Manx Grand Prix in August, this circuit is used by everyday traffic for the work commute, the school run, inhabited by tractors, buses and lorries.

Richard Petrie
BBC Sport at the Isle of Man TT

The Isle of Man TT is unique in that spectators are afforded the opportunity to line the course behind stone walls and hedges, in private gardens, just feet away from the projectiles that are racing Superbike machines.

Where else in the world would you get to see some of the world's most powerful and exotic machines blast past just a few feet away at speeds of up to 200mph?

Fans can marvel at the incredible exhilarating high-speed exploits of the finest exponents of road racing in the world - an intoxicating mix of the roar of engines, the smell of racing oil, the flash of colour as the bikes hurtle past on public roads at mind-blowing speed.

All the racers are regarded as heroes by the fans, revered just for taking part on this most demanding and challenging of circuits where there is little or no room for error and the 'kudos' for successful manufacturers is huge.

Speeds of up to 200mph on 37.73 miles of closed public roads, covering town streets, tree-lined roads, a jump over a bridge and the famous mountain section of the course.

It's one of the most iconic races anywhere in the motorsport world.

With Peter Hickman's record average lap speed of 136.358mph, it really is hard to get your head around.

Image source, Pacemaker

Image source, Pacemaker

Image source, Pacemaker

Image source, Pacemaker

Richard Petrie
BBC Sport at the Isle of Man TT

I may be biased but the Senior TT surely qualifies as one of the greatest sporting spectacles on the planet, one of the last genuine white knuckle events in motorsport and the ultimate test of rider and machine.

A supreme examination of skill, bravery, concentration and mechanical integrity.

After they leave the start-line at 10 second intervals the competitors hit 85mph in first gear and will be travelling at 160mph in just a handful of seconds before they plummet down the stomach churningly-steep Bray Hill section.

The event is a time trial in which riders race against the clock as well as each other.

With the island having enjoyed dry, sunny weather throughout the fortnight, there is plenty of rubber down the track, conditions which are conducive to fast lap times and perhaps record speeds.

Richard Petrie
BBC Sport at the Isle of Man TT

The TT is an event which evokes every conceivable range of emotions, where triumph and tragedy are all too often regular bedfellows.

The highs experienced as a result of the thrilling high speed action are tragically regularly mixed with gut-wrenching lows as riders pay the ultimate price on this most unforgiving of circuits.

The death this week of Spanish rider Raul Torras Martinez offered another reminder of the inherent risk and danger of racing over the Mountain Course.

The TT paddock is a tightly knit community and everyone is deeply affected by the passing of any one of their number.

Torras Martinez was a hugely popular figure in the world of road racing and deeply passionate about his racing.

We extend our deepest sympathies to his family and friends, all who mourn his sad passing at this time.

Image source, Pacemaker

Last year Michael Russell made history by becoming the first TT competitor to start every single race on the programme.

He took part in all eight races, solos and sidecars.

This year's extended programme, which includes two extra solo races, gave him the opportunity to take that record even further and start all 10 races.

Read more of what he said to BBC Sport here.

Image source, Pacemaker

Northern Ireland's Glenn Irwin reveals that he feels no urge to be competing at this year's races after becoming the fastest ever newcomer at the event last year with a lap speed in excess of 129mph.

The high-profile 2022 debutant has opted to concentrate on family commitments and his attempt to win a maiden British Superbike title with the Paul Bird Motorsport Ducati team this year.

Read more of what he told BBC Sport NI's Richard Petrie here.

Image source, Pacemaker

Richard Petrie
BBC Sport at the Isle of Man TT

The Supersport class 130mph club has this week welcomed its first and only two members! And their identity is no surprise.

In Wednesday's second race of the week for the middleweight class, Michael Dunlop and Peter Hickman both reached that notable landmark as they battled it out for supremacy on the final lap.

Dunlop emerged victorious in the race and also ended with the new lap record speed of 130.403mph. Hickman registered 130.219 in coming second.

Image source, BBC Sport