England’s women’s football World Cup defeat to USA was the most-watched British television broadcast of the year, with the success of Phil Neville’s team opening up the sport to new audiences.

A peak audience of 11.7 million tuned in to watch the end of England’s 2-1 defeat on Tuesday evening – more than the peak live audience for the finale of the hit drama Line of Duty.

An average of 10.3 million Britons watched the entire match – although the figures do not include the many people who watched it via the BBC’s online streaming services or those who watched in public spaces or pubs.

Large audiences have tuned in for all of the Women’s World Cup matches, which have all been shown by the BBC. Even matches not including England and Scotland have attracted millions of British viewers, suggesting a wider enthusiasm for women’s football as a whole.

The British viewing figures dwarf the paltry television audiences who have tuned in to watch the men’s cricket World Cup, which is being held in the UK but is available to watch only on Sky’s pay-TV service. This has prompted discussions over whether the final – which could feature England – should be shown on free-to-air television in a bid to drum up interest.

Although the BBC holds the rights to the Women’s World Cup, rival commercial broadcasters could be tempted to bid for future tournaments after seeing the large audiences attracted to the sport.

While the men’s World Cup is on a government-mandated list of sporting competitions that are required to be shown on free-to-air television, there is no such protection for the women’s equivalent. This is because it was not previously thought to be at risk of being snapped up by commercial rivals.

As a result, the shadow culture secretary, Tom Watson, has pledged to legally require the Women’s World Cup to be shown on free-to-air television if the Labour party wins the next election.