Up to 800 jobs are at risk across the UK at insurance giant Aviva as the company seeks to reduce its costs by �400m.

The insurer, which employs 6,000 staff in Norwich and 18,500 across the UK, said it would be making the cuts proportionally across the business.

Staff at the company were briefed yesterday about the new team structures, which Aviva said would simplify its business, making it more efficient.

The announcement comes after a turbulent few months for Aviva following the departure of chief executive Andrew Moss in the wake of a shareholders' revolt over executive pay and perks, and lacklustre share performance.

Announcing its half-year results earlier this month, Aviva said that operating profits had dipped 10pc to �935m following restructuring costs and lower returns from its life and pensions operations in the beleaguered eurozone.

The company did not initially put a figure on the number of jobs at risk following staff briefings yesterday afternoon, saying it was too early to say how many employees would leave the business.

This prompted an angry reaction from Unite union national officer David Fleming who said it was 'absolutely appalling that Aviva has consistently failed to disclose the total number of jobs being cut'.

Last night an Aviva spokesman confirmed up to 800 roles were at risk across the UK.

She said: 'Up to 800 roles are at risk, but in practice it will be lower. 'We have a very strong track record in keeping role reductions to a minimum. We will do this through natural turnover, closing unnecessary vacancies and looking for redeployment opportunities within Aviva, particularly as there will be some new roles in growth areas.'

In July Aviva chairman John McFarlane admitted that the insurance giant had stretched itself too far across the world and would axe a number of senior managers posts including at its Norwich headquarters.

But at the time he stressed that the city was key to its future plans.

In July Aviva refused to put a precise figure on the number of job losses, but said it would not impact on the vast majority of its customer-facing staff in Norwich.

As part of the earlier shake up, there were a number of senior executive changes, with the then chief executive of the Norwich-based UK and Ireland general insurance business David McMillan taking up a new role as director of group transformation to oversee the efficiency drive. He was replaced by Aviva Canada boss Robin Spencer.

The Unite union said that what had started out as an initiative to cut bureaucracy and duplication at senior and middle management levels under the banner of 'Project Simplify' had quietly turned into a major job cuts programme across the Aviva workforce.

Mr Fleming, added: 'Our members face being asked to pay the price of boardroom failure and Unite is dismayed that what started out as a shareholders' revolt on executive pay will result in a jobs cull. This is totally unacceptable.'