London mayor Boris Johnson has urged big retailers to pledge money towards a fund being set up to help small businesses affected by the riots.

The High Street Fund, launched on Wednesday, will provide hundreds of small businesses that were hit across England with initial grants of up to £2,000 to help with immediate cash flow problems, wages and costs associated with insurance claims.

Johnson told Retail Week: “I certainly expect big retailers to pledge. I think everybody should give to this operation and I hope big retailers will join.”

Fund chairman Sir William Castell, who is chairman of the Wellcome Trust, said he has spoken to John Lewis and Marks & Spencer.

He has collected £3m and hopes to raise £10m altogether, enabling the fund to give businesses a second round of grants.

He said it is in retailers’ best interests to support small local shops to ensure high streets thrive. He said: “We need to rebuild our high streets quickly. They’re under economic stress and don’t have the footfall at the moment to balance the books.”

Companies contributing to the fund include Barclays, BP and Lloyds, and the Greater London Authority has pledged £500,000. Claims can be made via Thehighstreetfund.co.uk.

Industry charity The Retail Trust has already separately pledged £50,000 to retailers hit by the riots.