After taking a nearly a year and a half to reach £500,000 worth of donations, the Pennies till-based microdonation scheme expects to have raised another £500,000 shortly after its two-year anniversary.

At the organisation’s two-year anniversary celebrations in London this morning, Alison Hutchinson, chief executive of Pennies, said that there has been more than 100 per cent year-on-year growth of the scheme in terms of donation numbers and total value.

While at its first anniversary Pennies announced it had hit A the 1m-donation mark, today Hutchinson said there have now been 3.5m individual donations via the scheme – which encourages people to round up their shopping bills and donate the change to charity – and that the organisation expects to have raised £1m by the end of this year.

Hutchinson also announced a raft of new retailers and payment providers which have recently come on board, or are in the pipeline, amid fanfare that the scheme has now reached a tipping point.

While she said the inclusion of new providers, like Barclaycard and Sage Pay, opens the scheme up to thousands more merchants, the chief exec also made a plea for more companies to support the Pennies. “We need payment and technology companies to come on board,” she said. “Just to make Pennies the standard offer.”

Broadcaster Fiona Phillips, hosting the event this morning, said that while there had been 70,000 donations made last week, “We estimate it could be 100 times that”.

Phillips also made a plea for the country’s largest retailers to sign up to the scheme, and propel it into a new phase. “We need the big supermarkets on board,” she said.

Speaking to an audience of mostly retailers being warmed to the scheme, minister for civil society Nick Hurd said: “I have a sense that something is changing out there.”

Hurd repeated the government’s longstanding support for Pennies, which was mentioned in the Giving White Paper. “Government takes Pennies very seriously – and has backed it,” he said.