Buy-to-let mortgages first appeared in the late 1990s, allowing people to borrow money to buy a second home and rent it out to tenants. 

For two decades it was a winner, as investors generated rental income from tenants and capital growth from rocketing house prices.

Becoming an amateur landlord became even more rewarding when interest rates were slashed after the financial crisis. That drove down mortgage costs while sending property prices to new highs.

At its peak there were up to 2.75million buy-to-let landlords, many of them ordinary Britons looking to build a second income for their retirement. 

Then everything went wrong.

In 2015, former Chancellor George Osborne launched a tax crackdown on buy-to-let, in what he claimed was an attempt to level the playing field with first-time buyers.

Many feared young buyers were being squeezed out of the property market as landlords loaded up on properties, often using the equity in their homes as a deposit.

Landlords lost thousands as Osborne scrapped wear and tear allowances and abolished higher rate tax relief on mortgage interest payments. 

He also slapped a three percent stamp duty surcharge on new investors.

Suddenly, buy-to-let wasn’t so lucrative. It wasn't much fun, either, with landlords unfairly demonised and blamed for the housing crisis.

Now the reputation of buy-to-let has taken another hit as new research exclusive to the Express shows just one in five landlords reckon their property investment has been a success.

Many are filled with regret and realise they’ve been naive, having failed to understand the risk, cost and effort involved in buying and renting out property.

They admit to losing thousands of pounds as a result and if that wasn’t enough, one in four says managing tenants has caused "mental health strain", according to new research from property tax adviser Cornerstone Tax.

Group chairman David Hannah said landlords are leaving the market in droves and the exodus is set to continue as higher mortgage rates squeeze profit margins. 

“The upcoming Renters Reform Bill contains radical plans to boost tenants' rights but some landlords feel targeted at a time when they are crucial in providing homes.”

Hannah said the government is rightly keen to drive rogue landlords out of the market but this is making life harder for those who act fairly, he said.

Troublesome tenants will prove hard to evict under proposed new rules, he warned. “Tenants need protection, but landlords ultimately need rights too.”

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Landlords also have to deal with costly new energy performance certificate (EPC) targets, with fines of up to £30,000 for falling short.

Many have had enough.

This is bad news for tenants as it is leading to a “chronic undersupply” of properties, driving up rents and making good properties hard to find.

Buy-to-let can still be profitable but the upfront costs are huge, including stamp duty, the survey, mortgage arrangement fees and refurbishing a property.

After that, landlords have to find tenants, chase deposits, prepare inventories and be prepared to repair dripping taps or leaky ceilings at a moment's notice. 

They also have the bother of filing an annual self-assessment tax return, while both rental income and property price growth will be taxed heavily.

I'm not surprised landlords are leaving in droves. Many have had enough.

This is good news for first-time buyers, who can now pick up old rental properties at reduced prices.

But it's bad news for tenants seeking an affordable rent from an honest landlord. Now they have even less choice than before.