Some examples cited include adverts from sub-1% deals, low rates that no longer exist, fast decisions in principles, and outdated criteria.

Brokers said the problem is being exacerbated by the fast turnaround of products, with some lenders changing their rates bi-weekly.

According to data site Moneyfacts, the average shelf life for residential products has varied significantly over the past year.

In May last year, the average shelf life of a residential product was 32 days. It then fluctuated slightly until January when it reached a high of 42 days.

Since then, shelf lives have plummeted, falling to 28 days in February and 21 days in April. The current shelf life of a listing stands at 22 days.

‘Dangerous territory’

Matthew Poole, director of Poole Family Financial, said: “As a mortgage broker it’s easy for us to spot something that doesn’t seem quite right when rates are advertised. But it’s not so easy for the general public when there are literally thousands of deals available at any one time.

“Mortgage rates are changing rapidly at the moment so if you see a really low interest rate advertised, don’t bank on being offered that rate when you reach out to the company advertising it.”

He added that companies that are using these kinds of adverts would be looking to “generate interest, and it will be a lead generation tool”.

“It’s dangerous territory to be advertising interest rates as they can change at any point without notice. Advertising rates that are no longer available is a breach of the Financial Conduct Authority’s (FCA) guidelines, where financial promotions should be clear, not misleading and fair,” he said.

The FCA guidelines also state that promotions and communications to customers should not be promoting products which they know are no longer available.

Graham Taylor, managing director of Hudson Rose, said that he had seen several examples of adverts for rates that no longer exist, mainly on Facebook and Instagram.

He said: “With the market rising as it is, it is currently very difficult to be confident in putting out specific product information.

“So perhaps such firms could be given the benefit of the doubt at being ‘caught out’ with sudden rate withdrawals. However, it is their responsibility to make sure that their adverts are not misleading and the cynic in me might think it is sharp practice to hoover up enquiries.”

Rhys Schofield, managing director at Peak Mortgages and Protection, said that when lenders were changing their rates so often, the public should “take any advert they see with a bucket of salt”.

He said: “My advice to the public is that it’s completely illogical to try to keep up with rates yourself because even professional, qualified brokers with advanced tech who do this for a living are working round the clock to keep up with rate changes.”

Social media adverts are like the ‘Wild West’

Brokers said that while rules around adverts for mortgages, which fall under the banner of financial promotions, were strictly defined by the FCA, they are often not followed on social media.

Scott Taylor-Barr, financial adviser at Carl Summers Financial Services, said there were clear guidelines around what content could be included, the wording, figures and font size for small print, to name a few.

“What I do find really frustrating is when adverts, usually on social media, blatantly ignore the rules,” he said.

Lewis Shaw, founder and mortgage expert at Shaw Financial Services, said that social media was the “scourge of financial promotions”, adding that it was like the “Wild West”.

“There are so many adverts that are misleading, inaccurate or disingenuous, mainly across Facebook and Instagram in my experience, and almost exclusively about debt consolidation. For most consumers, the best thing to do is take them with a pinch of salt and if you think it sounds too good to be true, remember that it always will be,” he said.

Importance of mortgage advice

Brokers said it’s important to seek out mortgage advice, and that doing extensive research is key.

Taylor-Barr said: “Getting really good quality mortgage advice is always going to pay dividends, but customers should be aware of anything that looks too good to be true, with mortgages or any other deals they see, because often these will be scams at worst or unscrupulous rogues at best.”

He advised customers to do research, go to the website via a browser and check out companies on the FCA register.

“That way you can feel confident you are dealing with a genuine, trustworthy, professional who has your best interests at heart,” he said.

Ian Hewett, founder of The Bearded Mortgage Broker said: “Always try and speak to a broker, some are fee free, some charge, most will give good service.

“Look at reviews, look at their social media, and have a chat with them to find out who you would like to work with. You would do the same for a babysitter, so why not do it when it comes to your finances.”

Our sister title – Mortgage Solutions – which originally ran this article, approached Meta, the parent company for Facebook and Instagram, for comment but had yet to receive a reply by the time of publication.