The London Brigade has urged people to buy takeaway food during the strike if they had been drinking at Christmas events to reduce the threat of kitchen fires.
FBU members have now taken strike action five times in recent months in protest at changes to pensions and their retirement age, which the union argues threatens older firefighters with losing their jobs or having reduced pensions.
The union said firefighters in their late 50s face the prospect of being sacked or seeing their pension reduced by almost half.
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Officers carried out first aid and paramedics were called to the scene, but the victim was pronounced dead a short time later.
Reviews described the lounge at Stansted as having ‘stained carpets’ which were ‘dusted with crumbs’ and a ‘sad-looking buffet’.
The demonstration in central London comes as pro-Brexit campaigners are joined by Nigel Farage for the next stage of the March to Leave.