The Conservative Party’s election war chest has been boosted by a £10 million bequest from the former boss of Sainsbury’s.

The donation from Lord John Sainsbury, who died in January 2022 at the age of 94, took total donations to the Tories to £15.4 million between July and September 2023.

It is also the single largest donation to the Conservative Party this year, with Electoral Commission figures published on Thursday showing the party has raised more than £37 million in 2023 so far.

The PA news agency understands that the donation was made to the Conservative Foundation, which was founded in 2009 to provide a long-term endowment fund that will pass on investment income to the party, rather than to finance routine campaigning.

The foundation funds a £250,000 bursary scheme for Conservative candidates who would not otherwise be able to afford to fund their campaigns.

Lord Sainsbury, whose cousin David Sainsbury is a major Labour donor, sat as a Conservative peer from 1989 and donated around £1.75 million to the party during David Cameron’s tenure as leader before backing the Remain campaign in 2016.

Other major Conservative donors included in Thursday’s figures were Graham Edwards, the party treasurer, who provided £2 million in “administration services”, and Malik Karim, a former treasurer, who donated £250,000.

The party also received £250,000 from Flowidea Ltd, owned by Swiss-born banker Sir Henry Angest, and £125,000 from Global Education Holdings Ltd, owned by Indian businessman Vishwajeet Rana.

Labour managed to raise £3.1 million in the third quarter of this year, taking total donations to £15 million for 2023. The party has also received £6.8 million in public funding.

Former Autoglass boss Gary Lubner continued his run of donating to Labour, providing another £687,500. He has pledged to donate £5 million to the party ahead of the next election.

The party also received £250,000 from former international poker player Derek Webb, building on a £40,000 donation in March, and £100,000 from financier and former Goldman Sachs banker David Blood.

The Liberal Democrats raised £2.4 million in the third quarter of 2023, including a £100,000 donation from former aircraft parts supplier Stephen Gosling, taking its total for the year so far to £6 million.

The Government recently increased the amount that parties could spend during a general election to around £35 million, up from just under £19 million at the 2019 election.