The Financial Conduct Authority (FCA) found that 40% of borrowers who took out a mortgage in 2017 will be aged over 65 when their mortgage matures – leaving them unable to save for a pension, and vulnerable to any financial shocks.

The 40% figure represents a huge change over the last five years. As recently as 2012, just 22% of mortgages were expected to run into the borrower’s retirement. But that number has nearly doubled as buyers stretch themselves to pay for escalating house prices.

Historically, buyers have taken out 25-year mortgages to pay for their home, and in 2007 the 25-year term was still the most common deal. But the FCA found that 30-year terms have now become the norm, with 34% of loans taken out in 2017 lasting 30 years or more.

Most lenders now allow mortgages of 35 years, while Halifax and Nationwide, the two biggest lenders, will offer loans with 40-year repayment terms.

Many first-time buyers are also delaying a purchase until they are in their 30s as they save to afford the deposit.

Despite the time of year, this is not a festive gift-wrapping session. Instead, the packages contain the possessions of a 63-year-old woman, moving out of her home at a far from ideal time of year.

Wendy (not her real name) has little choice, however. She is being evicted by her landlord – a Malaysia-based investor and owner of numerous UK properties – who is throwing out his tenant despite her never having missed a rent payment.

“I am literally being sick,” Wendy said in the run-up to her move. “I am absolutely desperate and housing associations will not help; it is a nightmare.”

This tale of a Christmas eviction may seem Dickensian but it is current, commonplace and seemingly frequently tolerated by local authorities. In many cases – including Wendy’s – it is also perfectly legal.

Legal no-fault evictions – called “section 21” in the jargon – have existed since 1988. They are controversial and there is now a parliamentary move to change the law – partly because of the type of antics highlighted by campaigners such as the Labour MP Karen Buck, who told a Westminster Hall debate on section 21 earlier this month how an unidentified landlord had bragged on social media about timing his evictions at this time of year. The post read: “If a tenant has annoyed me I wait to pull the trigger in mid-November to screw up their Christmas.”

Wendy’s rent was paid in full during her 12-year tenancy, despite longstanding problems at the property, which she says included seven years of a leaking roof. She suspects that she was the victim of a “revenge eviction” – a punishment for her commencing legal proceedings because of conditions in the flat.

The complaint letter sent by Wendy’s lawyer to the landlord’s estate agent, Winkworth, in March of this year, stated: “You were notified [about conditions] verbally by our client on a number of occasions … The defects at the property are causing an exacerbation of our client’s health issues. Our client is disabled and the damp is causing our client to suffer significantly.”

Ten weeks later and Wendy, who describes herself as “slightly disabled [with] crippled fingers”, received a section 21 notice from her landlord Bazmore Enterprise, a UK-registered company owned by Bujang Bin Ahmad Zaidi.

When asked by the Guardian to explain the decision, Kim Karpeta, a director of Winkworth’s Weybridge franchise, said: “If she hadn’t got lawyers involved and tried to beat the landlord up with a stick, she’d have probably been fine.”

Karpeta later said he “used the wrong choice of words and … did not present the situation in the correct light”. Bazmore’s lawyers added that Karpeta was not authorised to comment on its behalf and denied the eviction was retaliatory.

Before Wendy left her home the leaking roof had been fixed but the smell of damp would hit you as soon as you entered the two-bedroom flat.

A dark mould clung to some ceilings and around the kitchen window, which remained moist to the touch. There was a coldness to the walls, stained by dripping water, while the ceiling lights would flicker on and off seemingly at a whim.

The property appeared, by most modern standards, a miserable place to live – an assessment pretty well agreed by all parties. However, each side has differing versions about why problems went unsolved – and why Wendy was evicted just before Christmas.

Bazmore and Winkworth said Wendy was an awkward tenant, who did not always allow workmen access to the property to make repairs. They also claimed that other tenants in the block had complained about her.

Wendy argued that despite years of complaints to the current and a previous landlord, Bazmore’s eviction proceedings only commenced after she started her legal claim in March.

If that was the trigger, she would hardly be alone. Nearly half of all tenants who make a formal complaint about their housing suffer a “revenge eviction” by private landlords, according to research by Citizens Advice. Rules protecting tenants from revenge evictions exist but they do not always work and did not apply in Wendy’s case.

So who can tenants complain to?

The obvious answer might be the local authority, although many are under financial pressure and the IFS, an economics thinktank, calculates that council housing budgets were down 53% in real terms from 2009-10 to 2017-18.

Also, Wendy resides in a borough with a statistically weak enforcement record.

Elmbridge was one of 53 councils in England and Wales that did not make a single prosecution under the Housing Act during 2015, 2016 or 2017, according to responses to freedom of information requests made as part of an earlier joint investigation into rogue landlords this autumn by the Guardian and ITV News.

Furthermore, Elmbridge failed to impose a single civil penalty on a landlord during 2017-18.

Dan Wilson Craw, a director of the private renters’ campaign group Generation Rent, said: “Relying on cash-strapped councils to give tenants protection from retaliatory eviction is too fiddly. We need a stronger fundamental right over our homes – and that starts with abolishing section 21.”

Elmbridge did serve an improvement notice on Wendy’s property in 2015, which supposedly compelled the then landlord – and future landlords – to act.

Russell Moffatt, a former enforcement officer with the London borough of Newham in east London and now co-founder of the property licensing software firm Metastreet, inspected Wendy’s property in November, at the request of the Guardian and ITV News.

He said: “Councils, I’m sure, want to do more, [but] they are hard-stretched at the moment. An improvement notice was served. Could it have been enforced and more done? Yes it could have.

“Breaches of an improvement notice are a criminal offence if the work is not properly carried out … It could have been done but wasn’t done here”.

A spokeswoman for Elmbridge said: “We did follow up on the improvement notice, in terms of reminding the then landlord of their responsibilities and strongly encouraging them to act … All things considered, we were broadly satisfied with the progress that was made.”

She added that the council preferred dealing with landlords using “an approach built on advice and guidance, backed up by the threat of enforcement action”.

A spokeswoman for Winkworth said: “We acted in good faith throughout [the] tenancy. At all times, correct landlord and tenant procedures, as prescribed by the industry codes of practice and relevant legislation, have been adhered to.”