Hundreds of flood defence schemes have been left requiring repair after the UK was battered by record-breaking rain and storms, the Environment Agency said.
More than 20,000 properties were flooded as storms Desmond and Eva swept across the country and December became the wettest month on record, the latest update reveals.
The last month of 2015 saw 14 rivers across the north recording their highest ever flows, and 194 Environment Agency gauges registered their highest river levels on record.
The agency said its flood defences protected 12,500 properties from flooding during Storm Desmond, which swept in in early December, and 10,900 during Storm Eva at Christmas.
But 16,000 inspections of flood defences - 80% of the total - has found 660 schemes need repair.
Some high priority defences, including flood banks at Croston and St Michaels in Lancashire, have already been repaired permanently or on a temporary basis.
Some flood defence assets are still underwater and will be inspected when levels subside, the Environment Agency said.
Acting chairwoman Emma Howard Boyd said: "Our teams have worked tirelessly to repair flood defences and help communities in particular across Cumbria, Lancashire and Yorkshire get back on their feet after the terrible flooding we saw over December and January.
"Last week I visited Croston in Lancashire and saw the fantastic work that had been done to repair the flood bank and restore protection to residents in the village.
"This is the crucial work we are now focusing on to restore protection to those homes and businesses at risk."
Sir James Bevan, chief executive of the Environment Agency, said: "Vital flood recovery work is under way across the north of England as Environment Agency teams work to identify repairs and restore protection to communities.
"We will be using the £40 million provided to us by the Government to carry out these vital repairs.
"We will also continue to work with the Government on its flood resilience review, which will assess how we can be better protected in future from the type of extreme weather we saw in December."