Thames Barrier pushed to the limit by winter storms
The Thames Barrier is on the verge of hitting its maximum recommended closures per year - and that could prompt the Environment Agency to strengthen flood defences.
Tuesday night's closure was the 48th so far in 2014, nudging the recommended annual limit of 50, a figure it has already reached if two closures in December are added.
A worrying report by the quango on the future of the barrier said exceeding the target could see it "failing to unacceptable levels".
And it comes on the same week as figures have been released revealing 100,000 homes in east London and Greenwich could be flooded in the event of a failure.
The recommendation of 50 was made in an Environment Agency report released four years ago which said a new flood defence system was likely to be brought in some time after 2030.
It added: "The risk of the barrier failing is increased the more it is closed and frequent closures will affect the maintenance regime.
"The recommendation of the Thames Estuary 2100 project is to set 50 as the maximum number of times the barrier should close each year. This will reduce the chance of it failing to acceptable levels.
"Reaching this figure will mean we will need to intervene and improve the tidal defence system."
This could see plans for a new barrier - as well as an increase in height of the current one at Woolwich - brought rapidly forward.
However, a spokesman for the Environment Agency said the figure for 2014 was being treated as an anomaly.
"This is the wettest winter for 250 years so it's appropriate the barrier will be used more," he said.
"It might be that this year we do twice as many closures but next year could drop to 10."
The previous high had been 24 times in 2001.
In a report issued last week, Friends of the Earth claimed 103,807 homes across east London and Greenwich face a real risk of flooding - including 5,388 which are at significant risk.
The figures have the backing of Poplar and Limehouse MP Jim Fitzpatrick, who has called for greater spending on flood defences.
"The recent floods are a wake-up call on the need to do more to protect households from climate change," said Mr Fitzpatrick.
"Flood defence spending must take into account the impact of climate change, like more rainfall and higher sea levels."
The 100,000 figure covers the east London constituencies of East Ham, West Ham and Poplar and Limehouse, as well as the south London constituencies of Greenwich and Woolwich and Erith and Thamesmead.
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Aside from those areas, the Government's own Climate Change Risk Assessment estimates almost one million homes could be at significant danger of flooding by the 2020s - up from 370,000 currently.
Friends of the Earth London campaigner Jenny Bates said: "We must do much more to prepare for the impacts of climate change. Without proper investment in flood defences, hundreds of thousands more homes could be put at risk of flooding.
"Prevention is better than cure, so it's also vital that the Government redoubles efforts to stop climate change becoming worse."
And last week, Mayor Boris Johnson also called for a review of the Thames Barrier.
He said: "My information is that the barrier is good for another 75 years, but in view of the many times it has been in operation and continues to be in operation over the last few weeks and months it is only prudent to have a full review of its operations."