Thousands of BT engineers are to stage three 24-hour strikes in a dispute over a new bonus scheme.

Members of the Communication Workers Union (CWU) will walk out on April 14, 25 and 28 in protest at the productivity scheme, which they oppose as "divisive".

The union said although the scheme was voluntary, workers would come under pressure to increase productivity.

A union official said: "It is in everyone's interest that this management scheme to divide us is dumped. Industrial action is the only way to make BT listen to us, we have tried everything else."

The strikes will lead to delays in installation and maintenance of telephone equipment, the union said.

BT said it was disappointed the union had called strikes and appealed for more talks to try to avert the "futile" industrial action.

A BT spokesman said: "The company feels there is no need for industrial action, especially over a scheme which is already delivering financial and lifestyle benefits to many of the union's members."

About 6,000 engineers were in the scheme, which was paying bonuses averaging £62 a week.

He added: "BT believes a strike would be pointless and even at this late stage we would appeal to the CWU to return to the negotiating table."

BT said the scheme was crucial to the company's future success and brought "huge all-round" benefits.