The UK buy-to-let market must have signs of life, strong enough to be perceived even from overseas, because – hot on the heels of the Aldermore news – a new lender has entered the market this week.

Precise Mortgages is the trade name of a new mortgage venture backed by American private equity. The backers are NY-based investment firm Elliott Associates, recently linked with a bid for IT technology company Novell.

Starting this month (May 2010), they'll be offering three different buy-to-let mortgages, starting from a rate of 5.79 per cent at 75% loan to value. That rate is devised by adding 5.15 to LIBOR over a two-year tracker deal.

A downside for larger value loans is the 2.5 per cent arrangement fee, which needs to be paid straight up – rather than added to the loan – which will eat into the deposit a little. And this new venture won't appeal to professional landlords yet, as there is a limit of one property per investor. New-build properties are also disallowed.

Precise Mortgages has not unveiled any owner-occupier mortgages, but if you're a buy-to-let property investor this will add to your options. You'll have to arrange a quote through one of their panel of intermediaries, which includes L&G Mortgage Club, Mortgage Intelligence and Mortgage Next.

A new lender enters the UK mortgage market this week, making the most of all the savings money it has accumulated in the last 9 months.

The new entrant is Aldermore Bank. It's not a new entity: formerly known as Ruffler Bank, which for three decades lent mainly to businesses importing gaming machines from overseas, the bank was taken over last year by the venture capital firm AnaCap Financial Partners. With it came a name-change, and Aldermore Bank started offering saving accounts in summer 2009, making a name for itself with several best-buy table appearances on fixed term savings bonds.

Now, the bank has started lending on residential mortgages – including buy-to-let.

Buy-to-let investors who don't mind chancing it on the base rate might try their two-year discount mortgage from 4.98 per cent. Three and five-year fixed rates are available from 5.78 per cent. Excluded are new build homes and multiple property purchases.

To obtain an Aldermore mortgage means going through one of their intermediaries: L&G Mortgage Club and Mortgage Intelligence are among the names, as is Mortgages for Business.

If you're an owner occupier but you decide to live elsewhere for a short while, most people would assume it's OK to rent out your home.

However, on a residential mortgage you need what's called "consent to let" from your mortgage lender — and they're making it more difficult to let out your existing property in this way.

Lenders are beginning to charge higher fees, make you jump through hoops, or refuse to consent at all. Contrast this situation with the buy-to-let boom years when, in lenders' eyes, there was nothing wrong with short term letting as long as the mortgage repayments were kept up.

Previously, you might have faced a £100 admin fee at most. Now, your lender might require you to:

• attend interviews

• pay a higher interest rate or fee

• move to a buy-to-let mortgage deal

Buy-to-let mortgages typically have higher interest rates and stricter qualifying criteria than residential mortgages, meaning #3 there is as much an obstruction as #1 or #2.

Here are some specific mortgage lender illustrations:

• Intelligent Finance charges mortgage borrowers a lease fee of 0.5 per cent of the outstanding mortgage every six months — a significant extra cost for borrowers (on a £100,000 mortgage that's nearly an extra £1,000 a year).

• Yorkshire Building Society asks a £100 administration fee and puts up your mortgage interest by 1% if your loan-to-value is over 75 per cent

• Northern Rock avoids giving consent at all if your loan-to-value is above 70 per cent.

• Abbey interviews borrowers before giving consent and is likely to request borrowers to move onto a buy-to-let deal

• Halifax also demands an interview; borrowers must move on to a specific consent-to-let rate, priced similarly to a buy-to-let deal

However, some lenders are not so draconian:

• Nationwide has been known to agree three-year letting periods at no extra cost

• HSBC lets you rent out your property for 12 months without any extra charges

• Northern Rock charges £250 to allow you to let your property over 12 months

Warning if you're thinking of letting on the quiet

If all these restrictions tempt you not to tell your lender about letting out your property, be prepared for a penalty: on a residential mortgage you'll be in breach of your mortgage conditions, which affects your tenant as well as yourselves. Jump through hoops for a fair deal you might, but it's better than having your mortgage cancelled.

The other party to inform when letting out your property is your home insurer: without notice, they could invalidate your policy in the event of a claim. A tenant might not take the good care you do, so being uninsured is not something we'd want to face!