“Not making the Olympic team I was really just determined to come out here and show what I really could have done in Rio,” she said.

“That 12.40 got my confidence back.

“I knew I had it in me, I ran as hard as I could today.

“Good luck to the girls running in Rio – I’m just shocked right now!”

Only a little further down the roll of honour on the first of the two days of the Muller Anniversary Games came Britain’s Laura Muir, whose totally committed victory in the 1500m left a field including the Netherlands’s world bronze medallist Sifan Hassan in her wake and earned her a national record of 3min 57.49sec, surpassing the time of 3:57.90 set by Kelly Holmes in winning the second of her two gold medals at the 2004 Athens Olympics.

“I knew I was in very good shape and I wanted to come out here and do it justice,” said Muir, a 23-year-old veterinary student at Glasgow University who, unlike Harrison, is Rio-bound.

“I thought I was in four-minute shape, but to get the record here in the London 2012 Olympic stadium is unbelievable.”

Holmes swiftly tweeted: “Amazing run – knew you could do it, you’ve been running so well this year.

“Now on to Rio 2016.

“Records are there to be broken.”

That was the second British record of the night following the 41.81sec clocked by the victorious home women’s 4x100m quartet of Asha Philip, Desiree Henry, Dina Asher-Smith and Darryl Neita, the fastest time of the year so far.

Bolt, who has been receiving intensive treatment from German doctor Hans Muller-Wohlfahrt since pulling out of the Jamaican Olympic trials three weeks ago, retained his concentration as the field only got away at the third attempt and had established a clear if not decisive lead over the field as the stagger unwound in the final straight.

In what was his first 2016 outing over his favourite distance, the world 100 and 200m record holder was clearly working all the way to the line before crossing clear of Alonso Edward of Panama, who clocked a season’s best of 20.04 and Britain’s 2014 European champion Adam Gemili, who has returned to action after a serious hamstring injury and who also had a season’s best, 20.07.

Bolt appeared satisfied rather than elated after a victory that has established him fifth in the 2016 world lists behind the 19.74sec run by former world and Olympic 400m champion LaShawn Merritt at the US Olympic trials, and the 19.75 also run at the US trials by world silver medallist Justin Gatlin.

“I’m getting there,” said Bolt.

“I’m not fully in shape, I need more work.

“But over time I’ll be fine, I’ll just keep doing the work.

“I tried to go for the kerb but I don’t think I executed well.

“The key thing is I came out here and won but I’m always hungry for more.

“It is always great to come back here to London and compete, it is a lot of fun.”

Olympic and world triple jump champion Christian Taylor of the United States indicated his readiness for a Rio defence as he won in 17.78, the best recorded so far this season.

Pierre-Ambrose Bosse of France won the 800m in 1:43.88 as Kenya’s trials winner Ferguson Rotich could only manage third place in 1:44.38 ahead of Botswana’s London 2012 silver medallist Nijel Amos, who clocked 1:44.66.

The Emsley Carr Mile was won in 3:53.04 by Kenya’s Silas Kiplagat.

In the stadium where she won the Olympic heptathlon title four years ago, Jessica Ennis-Hill was encouraged to reach the high-powered final of the women’s 100m hurdles despite finishing eighth and last in 13.04.

Earlier in the evening Britain’s Katerina Johnson Thompson, who will also compete in the Rio heptathlon at the Rio Olympics, set an outdoor personal best of 1.95m in the women’s high jump in Rio, with Morgan Lake, who will be Britain’s sole selection at this event in the Olympics, also jumping a personal best of 1.92 in a competition won by Spain’s triple European champion Ruth Beitia with 1.98.

France’s world pole vault record holder Renaud Lavillenie, who will defend his title in Rio, put his embarrassing miscalculation at this month’s European Championships – where his defence failed after he elected to delay competing until the 5.75m mark and then failed to set a mark in windy conditions – as he earned a timely morale booster with a faultless progression to 5.90m before three failures at 5.97.

Victory in the men’s 100m went to France’s Jimmy Vicaut, who equalled his European record of 9.86sec earlier this season.

However, the superfast track didn’t do much for Vicaut or the rest of the field as he won in a relatively modest 10.02.