Heritage Underwriting has become the latest Lloyd's insurer to cut back on its UK liability business, as competition mounts in the sector.

The insurer has decreased its UK-focused portfolio by more than 20% in the past three years and insisted it would cut it back further if market conditions continued to intensify.

Richard Pexton, chief executive of Heritage, said: "In 2003, 60% of our book was in the UK liability sector. We are now down to below 40% of UK business."

"If the market remains competitive we will be shedding more of the UK business," he added. "We are not seeing at the moment that the UK market is changing.

"It is actually getting more competitive especially in non-US liability and property. We have very little property left now."

As a result of increased competition in the UK market, which has also prompted companies such as Brit and Amlin to reduce their portfolios, Heritage has diversified its business geographically into territories such as Australia, Canada and South Africa in order to maintain premium income.

Meanwhile, Heritage, which specialises in worldwide property and non-US liability, doubled profits in 2006 from £4.6m to £10.3m. Gross written premiums increased by 82% to £110.9m.

Pexton said that following a successful public floatation at the end of 2005, when the company raised £33m of new equity, it would continue to grow the business in 2007.

He said Heritage was currently in discussions with a number of teams about adding two additional business lines to the company's portfolio.

This followed the introduction of personal accident, financial institutions and US liability last year.