This represents a 30% rise from £10.3bn in February and a 17% rise from March 2011 when it was £11.4bn.
It was also the highest monthly total since September 2011 when gross mortgage lending was £13.6bn.
Gross lending in the first quarter of the year was an estimated £34.4bn, down from £37.8bn in the previous quarter but a 13% increase from the first three months of 2011 when gross mortgage lending reached £30.3bn.
Bob Pannell, chief economist at the CML, said: “The increase in our March lending estimate appears to be almost entirely due to stronger house purchase activity. The most likely explanation is that buyers wanted to complete their transactions before the end of the stamp duty concession on 24 March.
"The underlying picture for house purchase activity has been relatively buoyant in recent months. However, we would be surprised if we did not see a drop in transactions over the next few months, following the end of the stamp duty concession, especially as it will take some while for NewBuy transaction levels to build."
David Brown, commercial director of LSL Property Services, said: “The rush to beat the stamp duty deadline has warped the monthly lending figures out of all recognition, given the levels we are accustomed to since the credit crunch.
“However there are indications that lending is already falling back and that mortgage rates are rising for both new and existing borrowers alike as lenders face increasing funding costs.
“A dip in house purchase lending, combined with the end of the stamp duty holiday, is likely to drive up demand for rented homes even further, bolstering rents in the private rented sector.”
Peter Rollings, chief executive officer of Marsh & Parsons, added: “While rates are still relatively cheap historically, when you factor in the re-instatement of stamp duty for first-time buyers, it’s likely that many buyers at the lower end of the market will face an uphill struggle financially.
“It shouldn’t be forgotten that first-time buyers are the engine room of the market, and this will have the effect of dampening buyer activity on a national level.
“In London, the market has moved up a gear of late – despite the changes to stamp duty, with the sub £2m bracket especially vibrant. The capital is somewhat insulated against tightening mortgage conditions - with activity buoyed by buyers who are typically equity rich or cash buyers.
“However if lending does contract in the future, it will become increasingly difficult to view London as anything other than a different entity altogether to the national housing market.”
Michael Coogan, strategic adviser at Deloitte, said: “The mortgage lending figures for the first quarter of 2012 have been buoyed by transactions being brought forward to benefit from the stamp duty exemption.
"Now this exemption has been withdrawn, we can expect fewer mortgage approvals in Q2. However, a feel-good factor from the London 2012 Olympic Games and Diamond Jubilee celebrations should still ensure that this year’s mortgage lending will exceed 2011 levels.”
