Helsinki - Briton Mo Farah retained his 5 000m title at the European athletics championships on Wednesday while seven athletes were disqualified in the men's 400m heats for running outside their lanes.

World champion Farah cruised to victory nearly two seconds ahead of Germany's Arne Gabiuis, running the final lap in under 60 seconds to win the only gold medal decided on the opening day.

Seven athletes were disqualified in the five heats of the 400m and Briton Luke Lennon-Ford told reporters that it had been virtually impossible to stay in the lanes as the track was too narrow.

“One of the Finnish radio reporters told me they've changed the curve and they have blatantly made it too tight,” he said.

“I was only going 85 percent around the top bend and had to cut back to 65 percent around the next.”

His team mate Richard Buck was reinstated after successfully appealing the decision to disqualify him.

British steeplechaser Luke Gunn was forced to retire when he hit a barrier early in his race and will now miss the Olympics.

“It's been the sole aim for the last four or five years and I'm absolutely devastated,” he said.

French 100m defending champion Christophe Lemaitre won his first round heat in 10.14 seconds ahead of team mate Jimmy Vicaut. - Reuters