LONDON (Reuters) - UK wealth management firms are counting on new business from the moderately rich as they play down the impact of a possible exodus of the ultra wealthy from tax-hungry Britain.

The likes of steel magnate Lakshmi Mittal and Russian owner of Chelsea football club Roman Abramovich are coveted by firms, but the vast bulk of assets actually come from comfortably-off clients - the so-called mass-affluent - less able to relocate.

"There are a significant number of salaried people who are here, who work here and will always continue to work here and actually want to stay in England because they like it," said Ian Buckley, board director at Rathbones and head of the firm's trust and pensions division.

"We have a material number of those, but the vast majority of our clients do not have that amount of invested wealth with us," he said.

Mr. Buckley said developments in the UK tax regime had already caused some very wealthy families to move, and there are fears that new changes, including a new top rate of tax at 50 percent and a charge for non-domiciled residents, could speed the flow.

RBC Wealth Management tax director Louise Somerset said: "Quite a number of clients, not just non-domiciled ones but also UK-domiciled, are beginning to think about going elsewhere."

There are doubts, however, that those enquiries will amount to anything significant.

"You've had quite high profile business leaders saying 'this is ridiculous, we're taking our money offshore', but I think it's more headline-grabbing than anything else, said Katrina Hart, a wealth management analyst at Canaccord Adams.

Gerard Aquilina, vice-chairman of Barclays Wealth, who will address the Reuters Wealth Management Summit in Geneva next Wednesday, is aware that there will be some relocations.

"But London continues to accommodate an enormous talent pool of wealth managers, has the necessary infrastructure in place," he said.

According to the Scorpio Partnership, a specialist consultancy, many UK wealth managers have already realigned their business models to place less emphasis on ultra high net worth clients who are the most geographically mobile.

Catherine Tillotson, a partner at Scorpio, said wealth managers have found that a focus on the ultra rich - defined as holding assets of more than £10 million - to be costly as high service demands eat into profits.

More wealth managers are focusing on a much larger market of four million potential clients with between £100,000 and £10 million in investable assets comprising mostly of professionals and owner managers less able to relocate.

"I think most private banks feel it's good to have have an ultra high net worth offering because it makes it look as though you're moving in the right circles. Actually it's incredibly difficult to make money out of that client base. There aren't many of them and there's a huge number of players targeting them," said Ms Tillotson.

Hart at Cannacord Adams said a more onerous tax regime - including a top rate income tax at 50 percent for those earning over £150,000 a year - could actually provide a boost to the wealth management industry as more high net worths seek advice.

The new regime will also widen the differential between the top rate of income tax and the capital gains tax at 18 percent, which is likely to spark demand for advice on asset allocation away from dividend-paying assets and into growth stocks and other lower tax alternatives.

David Rosier, chairman of Thurleigh Investment Managers, was unconcerned wealthy clients, well-used to relatively high taxes in the UK, would see the changes as a tipping point, and noted wealth managers are often hired to soften a client's tax burden.

A greater concern for him is that a shift in the EU regulatory regime might make London a less appealing location for hedge funds, private equity or wealth managers themselves, causing a flow of talent away from London.

The UK wealth management industry has thrived off London's status as a banking hub with its concentrations of expertise.