Campaigners who organised a “flashmob” to protest against plans to turn one of Hampstead’s oldest pubs into a six-bedroom luxury house have attracted huge support for their cause.

The group of residents and business owners, who greeted supporters with mulled cider and festive food, descended on Hampstead High Street on Saturday to rally against plans that could see a final “last orders” called at The Old White Bear in Well Road.

The 300-year-old pub – which included late actors Oliver Reed and Peter O’Toole among its list of seasoned drinkers – is set to close in February. The new owner has lodged an application with Camden Council to turn it into housing.

With comedian Ricky Gervais and actor Peter Egan among almost 1,600 people lending their name to the cause, campaign organiser Leean Young said the prospect of losing another pub had obviously “struck a chord” with many in Hampstead.

“People were desperate to lend their support to the campaign,” said the 32-year-old, who runs a dog biscuit business from her home in nearby New End.

“They were shocked that Hampstead could so easily lose something that’s been here for over 300 years. Many are also fed up with yet another pub being lost to housing.

“Not only is it one of the oldest pubs in Hampstead, the Old White Bear has become a focal point for the community.

“It’s where residents meet each other, it’s where charities and schools hold meetings. It’ll be a massive loss to the community.”

News emerged in recent weeks that the pub had been sold to developer Braaid Ventures Ltd by debt-stricken Punch Taverns, one of the nation’s largest pub groups.

Restaurateur Jasper Gorst, who took over the pub in 2010 and turned it into a food-focused gastro pub, told the Ham&High he had made several unsuccessful bids to buy the freehold himself.

Property agent Simon Grainger, acting for the firm, said in a letter sent to local councillors on Tuesday that the venue “did not fulfil a specific community role” other than that of a pub and accused the campaigners of spreading “factual inaccuracies”.

He said: “The Old White Bear is now primarily a restaurant and has not operated solely as a pub for over four years because it was not making any money as a pub.”

He said the “proposals to convert [the] building into a family home will respect the building’s heritage”.

Objectors have until January 2 to express their views.