Hundreds of thousands of workers in the public sector are threatening to go on strike in opposition to the government's plans to cut the value of their pension schemes.
The coalition government says the rising cost of paying for the pensions of the UK's public sector employees is a big problem that must be deal with.
An independent commission led by Lord Hutton, the former Labour work and pensions secretary, has outlined proposals for the government to consider.
They include higher staff contributions, retiring later and moving staff from their existing final-salary schemes to cheaper, career average schemes.
This guide offers some basic information on the biggest schemes, outlining how much they cost to fund and the main benefits they offer to their members.
They are, in order of size:
Of these, the universities scheme is not included in the scope of Lord Hutton review.
In Scotland, the Scottish Public Pensions Agency oversees a number of public sector schemes, five of which provide similar benefits to their counterparts in England and Wales.
They are the NHS and teachers' pension schemes, and those for local government staff, firefighters and the police in Scotland.
In Northern Ireland there are separate but similar schemes for the civil service, health and personal social services, teachers, local government, police and firefighters.
Most of the schemes have undergone some significant changes in the past decade to reduce the cost to the employers.
The general trend has been to introduce a higher pension age, usually 65, but usually for new recruits.
In the civil service, new joiners are no longer offered a traditional final-salary scheme but a cheaper type of arrangement known as a career-average scheme.