More than 10 million people tuned in to the first Britain’s Got Talent live semi-final as the hit show builds up to this weekend’s final.

The show, which saw Welsh choir Cor Glanaethwy and dance group Entity Allstars get through to the final, pulled in 10.4 million viewers at its peak and an average audience of 8.9 million.

It is one of ITV’s big hitters and earlier this month almost 12 million viewers tuned into the third episode making it the most watched show of the year so far.

Cor Glanaethwy automatically made the final after receiving the majority of the public vote and the judges – Simon Cowell, Alesha Dixon, Amanda Holden and David Walliams – had to pick one act from the other two acts in the top three, Entity Allstars and Henry Gallagher.

Dixon, Holden and Cowell all voted for Entity Allstars, with Walliams giving Gallagher his vote.

The show went ahead despite a bomb scare earlier in the week when a 110lb (50kg) bomb, dropped during Nazi air raids in the early 1940s, was unearthed by builders working near Wembley stadium in north London.

Every night this week contestants will bid for a place in the final, with the hopes of winning the £250,000 cash prize and the opportunity to appear at the Royal Variety Performance.