They have given away more than 500,000 pancakes, delivered 35 tonnes of presents to people across the city and have even bought an entire street to a standstill while filling their headquarters with hundreds of boxes of food.

This year, however, they are short of a miracle.

What started as an experiment dreamed up by four friends in the living room of their West Hampstead house has turned into a worldwide phenomenon.

The Kindness Offensive is the world’s largest creator of “random acts of kindness” – which are staged like a flash mob because the group simply believe in the power of good deeds.

Decked out in their signature workmen’s reflective vests and hard hats, they have done everything from providing a blender for a family they met on Hampstead Heath, who were doing up their kitchen, to giving away flowers to hundreds of complete strangers in Trafalgar Square, and breaking two world records for the largest random acts of kindness.

This year the group’s annual toy drive, which makes the Christmas wishes of 4,000 orphans in the capital come true, is under threat because they have not been able to find a sponsor.

David Goodfellow, who founded The Kindness Offensive and whose West Hampstead house is their headquarters, said: “We’re unique in that we don’t accept donations from the public.

“This is purely for the people at no expense to them because it’s fun.

“We reckon corporations who operate on the high street and operate in our lives should be getting involved and doing something worthy for the community.”

The group deliver presents each Christmas out of a multi-coloured double decker ‘Kinder Bus’ given to them by clothing store White Stuff, and in 2011 Barclays sponsored their toy drive.

Today, however, their warehouse in Brent Cross stands empty.

It’s a stark contrast from last year when the group delivered gifts to every child who was in hospital in London on Christmas Day, as well as to children without parents or families who simply could not afford Christmas.

Though times are tough, the group is determined to succeed.

Mr Goodfellow said: “What we’re looking for is a local business who’s not doing anything for Christmas – or maybe even a lottery winner.

“What we need is a Christmas miracle.”

To contact the Kindness Offensive email contact@thekindnessoffensive.com