The past couple of years have seen one of the worst downturns in the housing market since World War II. According to Nationwide Building Society, the average property has fallen in value by around 20 per cent, with some areas – and some property types – seeing even deeper cuts to the value of homes.

But there are signs that the market is starting to improve. “I see 2010 as being the time when canny investors start to look again at the property market,” says Ray Boulger, mortgage technical manager at broker John Charcol. “They are seeing that property probably won’t get any cheaper and there is still demand for good quality accommodation in the right location from tenants.

And while property prices have fallen, rents have not seen a similar dip. According to research from Paragon Mortgages, a specialist buy-to-let lender, most landlords have been able to maintain their charges over the last couple of years, with a significant minority saying they have even been able to raise them.

But while properties are now cheaper, mortgages are not so easy to come by. “Many specialist lenders [which often provided investment mortgages] have closed their doors as a result of the credit crunch,” says David Whittaker, managing director of broker Mortgages for Business. “Those that are still lending have much stricter criteria.”

The biggest of these are the size of the deposit and what’s known as the rental income ratio. Buy-to-let mortgages are not the same as those for owner-occupiers; lenders use different rules when assessing an application. For a start, you’ll need a deposit of at least 15 per cent, and to access the best deals, you’ll want to have 25 per cent of the property value. The rental income ratio is how much of the rent will cover the mortgage. In the past, you may behave got away with the monthly mortgage payment being the same as the rent – know as 100 per cent. Nowadays, lenders insist on at least 125 per cent, which means that if your mortgage is £1,000 per month, the property must be able to attract a rent of £1,250 per month.

Once you’ve decided on property as an investment, there are various rules and regulations that you need to abide by. The absolute key law relates to gas. If you have any gas appliances in the property, they must be safety checked once a year and a copy of the safety certificate given to any tenants. Aside from the hideous possibility of being responsible for any harm coming to tenants as a result of a gas accident, failure to get a safety certificate could cost you a substantial fine or even a prison sentence.

You now also need to get an Energy Performance Certificate. They’re the same as those required within Home Information Packs for property sellers, and are there to show how energy-efficient the property is – fixtures and fittings like double glazing, insulated walls and modern boilers will all give your property a better score.

Insuring your property is also a different matter for landlords. Most conventional home insurance products don’t cover you if you have tenants, so you need to take out specialist landlord insurance to make sure you have proper protection.

Enquiries about commercial mortgage finance have jumped 44 per cent in the last month, according to broker Mortgages for Business.

The increase is down to increased confidence in the market, says the broker. One year on from the demise of Lehman Brothers, investors and businesses feel ready to re-enter the market.

Steve Olejnik, head of sales said: “The largest increase has been in placing traditional mortgages for trading businesses and commercial investments – but we’ve seen more HMOs, limited company buy to lets, residential developments and semi-commercial enquiries, too. Mortgages for Business have been dealing with commercial mortgages for the past 20 years and none of us have seen an uplift like this before.”

MD David Whittaker said: “This explosion in commercial business is the result of the recent run of house prices increases. Price rises are encouraging small developers to review projects that were not viable at the beginning of the summer. Suddenly, developers need to finance the purchase of sites to build properties on so they can have stock ready for sale in the summer of 2010.”

Whittaker added that most of the major high street lenders are still very risk-averse, and it’s been the boutique firms who are jump starting the commercial finance revival.

“We are experiencing this upswing because high street banks are unwilling to support new projects. They’re still trying to bolster their balance sheets, and demonstrate greater liquidity and return on funds. So borrowers are turning to specialists like us.

“Furthermore, our relationships with the main commercial lenders – including Aldermore – have really come through for us recently. This is funding that is not accessible to a large number of brokers. As a result, we’ve been placing a number of complicated deals that our peers haven’t been able to handle.”

Base Commercial Mortgages Limited, the specialist commercial mortgage lender which was forced to stop lending last year as a direct result of the credit crisis, is planning to restart lending via a limited panel of commercial finance brokers.

So far, Mortgages for Business has joined the panel, with more intermediaries to sign up imminently. Product details have not yet been announced yet, but David Whitaker, chief executive of Mortgages for Business suggested that the company is looking to launch slowly over the summer, and then really start promoting its services to the wider market as the industry heats up in the autumn.

The decision follows the recent acquisition of Ruffler Bank by Base’s backers, AnaCap Financial Partners, which gives Base access to retail funding. Base and Ruffler Bank are in the process of merging their operations to create a strongly capitalised business which is ideally positioned to provide a competitive range of property and asset finance facilities to small and medium sized businesses throughout the country.

“Base’s return to the market is a good sign for the commercial finance industry,” said Whitaker. “Because they’re not the biggest player, the amount they lend is unlikely to kickstart everything else, but I think it will increase confidence throughout the market.

Mark Stephens, chief executive at Base, said: “We’re delighted to be back in the commercial mortgage market once again, but are very mindful that we need to maintain a tight control over both business quality and volumes.”