September lending was still 10% higher than the £16.2bn recorded in September last year.
Lending for the whole of the third quarter was £55.5bn, an 8% increase from Q2 and 13% increase on the £49.2bn recorded in Q3 2013.
Bob Pannell, CML chief economist, said: “Uncertainty over when we will see the first increase in UK base rates is exacerbated by weaker growth prospects in several major economies, including the eurozone.
“Recent indicators and policy actions corroborate our view of a gentle easing in market conditions. There is growing evidence that mortgage lending activity, and the housing market, are sitting on a plateau.”
The CML commented that house price growth is slowing as London’s pronounced recovery runs out of steam.
But the council added that the markets outside London and the South East will continue to experience fairly modest recoveries.
Andy Knee, chief executive of LMS, said: “This further evidence of a cooling in the market should provide some much needed relief for first-time buyers who could experience reduced competition in purchasing a home and a slower ascension of house prices as a result.
“Lender appetite also remains healthy, as long as hopeful buyers meet their lending criteria.
“However, buying a house remains no mean feat and for more people to stand a chance of entering the market place, schemes such as Help to Buy are critical in offering a helping hand to get more young people onto the property ladder.
“Assistance to aspirational first-time buyers has therefore improved their chances of buying a home but should not be curtailed too soon.”
Mark Harris, chief executive of mortgage broker SPF Private Clients, added: ‘Gross mortgage lending dipped in September compared with August indicating that buyers may have concerns about the prospect of an interest rate rise.
“There is also a sense that economic recovery in Europe is fragile at best, which does nothing for consumer confidence when it comes to committing to something as costly as a property purchase.”