Thousands of Brits could be entitled to a massive tax refund from HMRC, experts have said.
On average, claimants could be owed £2,500 for an initial four-year claim and around £929 a year after that.
The data has been collected from RIFT Tax Refunds and appears to highlight a problem whereby people working in particular industries are unaware of their entitlement.
The stacks of cash have piled up through people either not claiming or forgetting to claim their expenses for things like fuel, GlasgowLive reports.
The money has been built up due to unclaimed tax relief available for people who spend money on work expenses.
Who is likely to get the tax refund?
The data collected has found that people working in construction, security, offshore oil and gas or within the armed forces are most likely to be owed the money.
People who are self-employed within the construction industry could be due the biggest payday, with average claimants receiving refunds of £1,698.
On average, those working full time in construction who aren’t self-employed could also be due an average of £1,244.
People in the armed forces could be due a payday, with some being eligible for a refund of £1,095.
On top of this, offshore oil and gas workers could be set to see £1,122 and security workers £959.
RIFT, which gathered the data, is understood to have facilitated some cases climbing as high as £18,000, with bigger sums tending to have accumulated from frequent travel to a range of locations requiring spending on accommodation and other things like food and drink.
The firm’s CEO, Jan Post, said: "The thought of tackling the taxman can be a daunting one and so the vast majority of us don’t even consider whether or not we could be owed a tax refund, particularly when working within full-time employment.
"However, there are a whole host of reasons that you could be owed money, such as travel between numerous sites of work, related meals, or overnight accommodation.
"While these tend to be more prominent within certain sectors, we frequently work with employees from all areas of life who find they are owed a considerable refund that would have otherwise gone unclaimed."
The government says you might be entitled to get a payout from the expenses tax relief if:
- You use your own money for things that you must buy for your job.
- You only use these things for your work.
The Gov.UK site also adds some of the things that may bar you from a payout. You cannot claim tax relief if your employer gives you:
- All the money back.
- An alternative, for example your employer gives you a laptop but you want a different type or model.