The Conservatives raised more than 10 times as much as Labour last week, partly thanks to a donation of over £1m from the theatre producer behind The Book of Mormon and The Phantom of the Opera.

John Gore, whose company has produced a string of hit musicals, gave £1.05m as part of the £3.77m received by the Conservatives in the third week of the election campaign.

In the same time, Labour received only £331,499.

The Electoral Commission only publishes details of donations over £7,500, so the smaller donors who make up most of Labour’s fundraising are not identified. Almost all Labour’s larger donations came from unions, including £159,500 from Unite.

The new figures show the Conservatives have received £15.2m since the start of 2017, while Labour has received £8.1m. The large donations came as the poll lead held by the Conservatives and Theresa May appeared to fall following controversies around her social care policy.

In the week starting 17 May, the Liberal Democrats received £310,500, of which £230,000 came from the Joseph Rowntree Reform Trust and £25,000 came from the former BBC director general Greg Dyke.

The Women’s Equality party received £71,552, with Edwina Snow, the Duke of Westminster’s sister who is married to the historian Dan Snow, giving £50,000. Ukip’s donations fell dramatically to £16,300 from £35,000 the previous week.

Political parties can spend £30,000 for every seat they contest during the regulated period. There are 650 seats around the country, meaning that parties can spend up to £19.5m during the regulated period in the run-up to the election.

Other large donations to the Tories in the third week of the campaign included £500,000 from JCB Service, which is run by the manufacturing billionaire Anthony Bamford. Lord Bamford, who strongly supported the leave campaign, received a peerage from David Cameron in 2013.

John Armitage, founder of the Egerton Capital hedge fund, also gave £500,000, bringing his donations this year to £1.125m. Mark Coombs, chief executive of the investment manager group Ashmore, gave £300,000.

Jersey House (Developments) Ltd, which is owned by the telecommunications entrepreneur Charles Wigoder, gave £250,000.

The haulage millionaire Steve Parkin gave £125,000. Parkin, who reportedly paid Robbie Williams £1m to perform at one of his parties, founded the delivery business Clipper Logistics.

The large sum from Gore is believed to be his first political donation. He is a seven-time Tony winning and Emmy-nominated producer and owns the John Gore Organization, which is headquartered in New York. The company presents shows, including Wicked and Jersey Boys, across the US, Japan and in London’s West End. Gore’s early investments included the original London production of Cats.

Last week, it emerged that the Conservatives had raised £1.6m in the second week of the general election campaign while Labour raised £383,000.