London remains attractive for the world's billionaires, but estate agents would like to see more done to attract them. Agents for property in the £10 million-plus bracket are reacting to the budget with caution.

"Banishing non-doms is not a good move at all, since the Exchequer raises some very valuable earnings that will now be lost," says Trevor Abrahmsohn of estate agent Glentree International. "You can't be 'open for business' but at the same time issue this policy, which will be off-putting for some much-needed wealth creators from abroad who would otherwise invest in this country.

"I'm not sure of the good sense in raising stamp duty to 12 per cent in the autumn statement of 2014, since the cost of moving above £1.5 million is now 15 per cent (when you include agents' and solicitors' fees) and this is a big hurdle to jump over - hence the muted activity in the marketplace."

Mr Abrahmsohn calls on the government to force buyers and sellers to share the stamp duty. "This will give the purchaser more money to spend, which will help the flagging market, and impose a small tax on the seller that, frankly, should be affordable since all the capital gain is free of tax."

At the top end of the market, Paul Davies London has transformed the top floor of a block in Knightsbridge into a single 10,0000-sq-ft penthouse - said to have the largest private rooftop terrace in Knightsbridge.

Recently let to actor Tom Cruise as his London pied-à-terre, Wellington Court is on the market for £35 million with estate agent Wetherell. It has six bedrooms, jacuzzi room, cinema room, gym, treatment room and music room. Formerly the second Duke of Wellington's riding school, Wellington Court was first developed for residential use in the 19th century.

The penthouse has six terraces with views over Hyde Park, Mayfair and Knightsbridge. Accessed through full-height glass bi-folding doors, the main lounge terrace spans 1,000 sq ft with views on to the Serpentine. The terrace includes a covered dining area for 12 people, and seating area with parasol, as well as lounge seating with fireplace and TV.

The interiors, by Paul Davies, are a throwback to 1920s Art Deco, with mirror-lined ceilings, black walnut oak parquet flooring and Italian marble bathrooms. The music room includes a Swarovski crystal-lined bar; the kitchen has African black marble worktops with Miele and Sub Zero appliances, and green Lalique-style chandeliers.

Mr Abrahmsohn praises the government for its handling of the economy, which he sees as a major prop for the property market. "It is very good news indeed that the UK is growing at one of the fastest rates of the advanced economies of the world. UK corporation tax is already low by international standards, at 20 per cent, and will fall to 18 per cent over the next five years. That is an incredible achievement," he says.