Firefighters in England and Wales will stage a fresh strike today in their long-running dispute with the Government over pensions.
Members of the Fire Brigades Union will walk out for two hours at 6.30am - the ninth stoppage since September.
But under the terms of an agreement between the FBU, central government and fire services, strikers will return to work if there is a major emergency that might lead to large numbers of people being put at serious risk. Fresh storms are expected today, during the latest strike.
The Metropolitan police have urged the public not to panic as back office police staff in London join the firefighters strike, because they have "tried-and-tested" continuity plans.
A spokesman said the Met had taken the "very difficult decision" to cancel annual leave for some specialist officers, in order to fill the void.
The PCS has now informed the Met that they intend to take strike action on New Year's Eve - one of the days when demand for our services is highest. We have tried-and-tested business continuity plans for all eventualities, including industrial action.
These ensure that critical functions performed by police staff are performed by police officers who are fully trained in those roles.
To ensure we are able to implement these plans, we stopped granting any further requests for annual leave or days off for officers and staff in a number of key areas for New Year's Eve in mid-December.
The fire minister has expressed his gratitude to the Fire Brigades Union for agreeing to recall firefighters in Kent and Surrey from a planned strike in light of the flooding:
I am grateful to the FBU national team for the implementation of previously agreed return to work protocols for Kent and Surrey given the adverse weather conditions and flooding that are currently being experienced in those areas.
Across the rest of the country, robust contingency plans are in place to make sure people remain safe over the festive period.
Firefighters are being asked to pay "£4,000 per year" out of a monthly take home of £1650, the head of the fireman's union told Daybreak.
FBU General Secretary, Matt Wrack said: "that is a huge chunk of their salary - one the highest in the public or private sector, for a pension which takes no account of the job they actually do, the physical demands.
"It is based on expecting someone of 60 to meet the same fitness standards as someone in their 20s. We think that is ludicrous."
The Christmas Eve firefighters strike has been dubbed "unnecessary" and "completely cynical" by the fire minister.
Brandon Lewis was adamant contingency plans were in place should the worst happen but urged people to be extra careful around candles and when cooking.
I met with the FBU on 4 December to continue discussions but their actions today show that they are not serious about resolving this dispute, which simply further damages firefighters' standing with the public.
The deal on the table gives firefighters one of the most generous pension schemes in all the public sector.
A firefighter who earns £29,000, and retires after a full career aged 60, will get a £19,000-a-year pension, rising to £26,000 with the state pension.
An equivalent private pension pot would be worth over half a million pounds and require firefighters to contribute twice as much.
Fire chiefs are urging party goers and those staying home to be extra vigilant after the firefighter strike starts at 7pm tonight.
Members of the Fire Brigades Union will begin industrial action at 7pm for five hours tonight. Further walk outs are expected on NewYear's Eve and January 3.
London Fire Commissioner Ron Dobson explained: "Contingency plans are in place but we're urging people to take care, to be sensible, and to remember that fire brigades could be very busy during the strikes.
"Make sure you keep candles well away from anything that could catch fire and switch off fairy lights when you go out or to bed.
"If you're preparing a festive feast, it's a good idea to keep an eye on cooking to prevent kitchen fires. That way your turkey will be cooked to perfection and you'll avoid having a fire."