Razor wire, roadblocks and machine-gun-toting police will greet the world's top financial leaders when they fly to a Sussex mansion next weekend.

Preparations are well under way to transform the 93-acre luxury venue of the G20 summit into a fortress when ministers and central bank governors from the European Union and 19 of the world's richest nations meet to discuss the global financial crisis.

Visitors to the meeting, including the UK's Chancellor Alistair Darling; Timothy Geithner, Secretary of the Treasury in the US and Kaoru Yosano, Japan's minister of finance, will fly by helicopter into the South Lodge Hotel, just south of Lower Beeding, near Horsham.

Sussex Police have confirmed they have been working with HM Treasury to plan security for the event.

Officers have been granted a footpath and bridleway closure order by West Sussex County Council for the duration of the conference at the venue.

Any members of the public using the closed footpaths or bridleway will be approached by police.

A spokeswoman for Sussex Police said: "Police will be present on the site, at the invitation of the landowner and the South Lodge Hotel Management, and in support of G4S, an international security solutions group.

"Our key aims are to ensure the safety and security of both visitors to the venue and to local communities and businesses, as well as ensuring minimum disruption to those who live and work nearby or who are travelling in the vicinity."

Although costs and further details for the operation have not been revealed, security at the site is likely to mirror the £6.1 million operation planned for Brighton when it hosts the Labour Party conference in September.