Olympic champion Ingebrigtsen suffered a shock defeat to Jake Wightman in Eugene last year, but this year's world leader in the distance was widely considered favourite for the title in the Hungarian capital with the defending champion absent due to injury.

Ingebrigtsen had beaten Tokyo 2020 bronze medallist Kerr in his heat and the semi-finals, when he made gestures to the crowd on the final straight, and led for most of the final.

However, Kerr - a team-mate of Wightman's at Edinburgh Athletic Club - stayed within range and moved side-by-side with Ingebrigtsen on the final bend.

Kerr then hauled his way to victory in 3min 29.39sec, forcing Ingebrigtsen to settle for silver for the second year running in 3:29.65.

There was a double Norwegian presence on the podium with Narve Gilje Nordås' bronze in 3:29.68, but the evening belonged to Kerr who secured back-to-back British 1500m titles.

"Those last moments of the race will be engraved on my brain for a very long time," Kerr said afterwards.

"I knew I had him with about 50m to go.

"I ran that last lap as well as I could and today it was all heart, all guts and remembering all the really hard yards it took me to get here.

"It's very hard to be the favourite and Jakob has a million things going on with world record attempts and multiple events.

"For me this is the be all and end all. You saw about 16 years of emotion at the end there."

Ingebrigtsen said he "had a good race but I feel a little bit unlucky not being able to do what I have been doing the whole season".

Wightman claimed on British public service broadcaster the BBC Ingebrigtsen had "under-estimated how well he was running".

Kerr received a gold medal from World Athletics President Sebastian Coe, a fellow Briton and two-time 1500m Olympic champion afterwards.

There was also a thrilling end to the women's pole vault final, in which there was nothing to choose between Australia's Nina Kennedy and Olympic and defending world champion Katie Moon.

They shared a gold medal after both clearing 4.90 metres on their final attempts.

Wilma Murto of Finland took bronze with a 4,80m clearance.

The other two finals provided dominant displays from the gold medallist.

Marileidy Paulino of the Dominican Republic upgraded her silver at the Tokyo 2020 Olympics and last year's World Championships in Eugene to gold as she powered to victory in the women's 400 metres final in 48.76sec.

Natalia Kaczmarek of Poland earned silver in 49.57, with Sada Williams of Barbados taking bronze for the second year running with a time of 49.60.

Norway's Olympic champion Karsten Warholm reclaimed his men's 400m hurdles title with victory in 46.89.

There had been controversy in Warholm's semi-final victory with claims he had illegally jumped one of the barriers, but he brushed that aside to underline his domination of the discipline in the final.

Kyron McMaster earned the British Virgin Islands' first World Championships silver in 47.34, and Rai Benjamin of the United States took bronze in 47.56.

In the 100m hurdles semi-finals, defending champion Tobi Amusan required a strong finish to win her race in 12.56.

She admitted "there is a lot I have to tune up but I will be ready for tomorrow".

Amusan was cleared to compete days before the World Championships when a Disciplinary Panel deemed she had not committed an anti-doping rule violation, after being charged by the Athletics Integrity Unit with whereabouts failures.

The decision was expected to be published today, but has not yet been released.

Emma Coburn of the US failed to make the women's 3,000m steeplechase final first the first time in six World Championships appearances after finishing 10th in her heat.

The evening session had begun with an impressive solo run from Latvia's under-20 European champion Agate Caune in the women's 5,000m, moved from the morning session due to high temperatures in Budapest.

Caune led for almost the entire race, and although eventually caught by the decorated trio of Beatrice Chebet of Kenya, Gudaf Tsegay of Ethiopia and Margaret Kipkemboi of Kenya, she qualified for the final in fourth place with a personal best 15:00.48.

The World Athletics Championships is due to continue tomorrow with finals in the men's and women's 35 kilometres race walk, men's long jump and 400m, and women's hammer throw, 100m hurdles and 400m hurdles.