Aviva Plc, Britain's second-biggest insurer, said it planned to shed 384 jobs following the expiry of a life and savings joint venture with Royal Bank of Scotland.

The job cuts, to be phased in over a year starting in the second half of 2012, reflect the closure of the joint venture's dedicated administration centre at Bristol, Aviva spokesman Steve Colton said.

The move comes less than a month after Aviva almost halved its Irish workforce with 950 job losses, the biggest round of redundancies by a single company in Ireland in two years.

This announcement takes the total number of jobs cut by Aviva in the UK and Ireland in the last month to 1,500, and is unacceptable, the Unite trade union said in a statement.

Insurers are under pressure to cut costs as rock-bottom interest rates eat into investment returns, eroding profit margins.

Rival insurer Standard Life last week announced 95 compulsory redundancies at its UK customer service division as part of a plan to take out 100 million pounds of costs by 2012.

Aviva said it would find new roles for affected employees where possible.

We will of course do everything we can to redeploy the people impacted by these changes, the company said.

Aviva shares were 1.3 percent lower at 311 pence by 2:25 p.m., underperforming the FTSE 100 share index, which was down 0.1 percent.

(Reporting by Myles Neligan; Editing by David Holmes)