Lenders have piled back into the rental market over the last year, considered risky during the downturn, as stricter mortgage regulations have hurt their profits.
Andrew Montlake of mortgage broker Coreco said: "The likes of Natwest and Santander have got back into the buy-to-let market. This has driven rates down to levels never seen before."
This buy-to-let surge contributed to the quarterly rise of 0.5pc in all residential loans outstanding in the third quarter of the year to £1,256 billion, the Bank of England reported.
Jonathan Harris, managing partner of Anderson Harris, said: "There is a general feeling that buy-to-let lending is a viable option again, although it is not the free for all of 2006/7.
"The rigours of the mortgage market review, introduced in April, and the capping of the number of high loan-to-value mortgages, have restricted the money coming into the lenders hence the focus on buy-to-let."
The increase in credit availability for buy-to-let mortgages has coincided with an increase in the number of wannabe-landlords.
People are holding on to their urban home, remortgaging it, switching to a buy-to-let product, taking out some equity and using that to buy a larger country property, Mr Montlake said.
"We are seeing this particularly in London as homeowners see the benefit of keeping London property as a long term investment." Despite a short-term fall in London values, many are counting on the future capital appreciation on London property.
Here are some of the best buy-to-let mortgages available, according to Coreco. This graph shows 60pc loan-to-value products:
And this one shows the best buy-to-let deals for 75pc loan-to-value products: