Turner Contemporary has launched a fund-raising appeal - already backed by a senior banker - as it comes close to welcoming its millionth visitor in its third year.

The Margate gallery aims to set up a £20 million endowment that will fund artistic work well into the future amid concerns over expected public funding cuts.

John Kampfner, chairman of the trustees, appealed to individuals and companies to become patrons and support the gallery. However successful it was, public funding would “inevitably decline,” he warned.

He said the milestone of a million visitors would be an extraordinary occasion and underlined the importance of Turner.

“This really has become one of the great art and cultural venues of the UK and further afield. In order to continue to present international art in Margate and Kent, we will have to strain every sinew much more than we have had to so far in terms of private philanthropy and other revenue-raising events. It is vital to the regeneration of this wonderful town.”

The campaign has been kick-started by a £530,000 gift from Goldman Sachs Gives which, with match funding, has risen to £1.06m.

Margate-born Peter Selman, now co-head of Americas Equities Trading and Global Equity Derivatives Trading at Goldman Sachs in New York.

Mr Selman was born and grew up in Margate, living in the town until the age of 18. He left Margate to study for an MA in Economics at Cambridge University in 1994 before moving to London and then New York in 2007.

Mr Selman said Turner Contemporary had been “so transformative for the town of Margate. I hope this gift from Goldman Sachs Gives contributes to the long term security of the gallery and will be the catalyst for many other gifts in future.”

Director Victoria Pomery said: “We are very focused on securing the long term future of the gallery and our aspiration is to build a £20m endowment pot, generating a vital and sustainable income stream for the gallery in future.”

She added: “The combined £1.06 m is a fantastic start to the endowment campaign. We are now looking for other individuals and companies to step forward and help build this pot and secure the gallery’s future.”

• More details about potential donations from Lhosa Daly at ldaly@turnercontemporary.org or call 01843 233000.