United, which is under pressure from shareholders to cut costs, said it would no longer sell policies where premiums are collected by monthly visits to the customer's home. Alan Frost, chief executive, said job losses would be necessary but refused to say how many.
The move follows similar decisions in the last four years by the Prudential and Pearl amid complaints that high selling costs made the practice uneconomic. Britannic Assurance is the only large insurer to continue the practice.
United's management is under pressure to cut costs from shareholders following the disastrous merger between United Friendly and Refuge which gave birth to United Assurance two years ago.
While a third of the sales force has been cut, no savings have materialised, sales have slumped and the shares have underperformed the sector by 40 per cent.
Full-year profits announced yesterday were down from pounds 226m to pounds 193m and the shares fell 3 per cent to 543.5p.
Alan Frost, United's chief executive, said: "This is a massive change to the organisation and it's positive for the sales force. But it's an enormous jolt."