Bosses at a business estate revealed a “big organisation” is looking for a 60,000 sq ft premises where it could create 400 jobs.

Executives at Discovery Park made the announcement as they gathered politicians and bosses on its lawns for a garden party to mark its fifth birthday.

The series of offices and laboratories is home to 150 companies employing about 3,000 people.

It was launched in 2012, a year after Pfizer announced it was closing the site with the loss of about 2,400 jobs.

In the end, the drugs company retained some of its research and development operations, employing about 700 people, and the park has become a “multi-business science hub” according to bosses.

The site was acquired by investment company Discovery Park Estates Limited in November – who invited officials from Kent County Council and Dover District Council to the celebrations.

The hint at a “big” new tenant was made by chief executive Toby Hunter, who said: “Having been in property for 30 years, it’s an honour to say I have never felt so proud to be part of a business like I do with Discovery Park.

“It’s an amazing place to be and a fantastic place to work, and everyone should be rightly proud of what they’ve created here.”

Work is due to start in November on 50,000 sq ft of new lab space, which will create space for up to 300 new chemists.

Cllr Paul Watkins, leader of Dover District Council, said: “Discovery Park is a beacon of opportunity for high-tech skills and jobs in the Dover district.

“Five years on and the site is now writing the next chapter in the story of Sandwich as a centre for pharmaceutical and technological innovation.”