When do the old £1 coins expire? Everything you need to know

At midnight on Sunday (15 October), the old £1 pound coins will cease to be legal tender after 34 years and will gradually be withdrawn from circulation.

The Royal Mint introduced the new £1 coin on 28 March, describing it described it as "the most secure circulating coin in the world", while the end of the road looms for the old "round pound".

What do I do with my old £1 coins?

The current coins, which replaced the old £1 note on 23 April 1983 and over two billion round pound coins have been produced since they entered circulation.

However, the coins will cease to be legal tender on 15 October, after the new pound coins were introduced earlier this year.

From Monday, they will no longer be accepted in shops and by vending machines, although businesses and consumers will still be allowed to deposit old coins in post offices and most high street banks.

Baroness Neville Rolfe, commercial secretary to the Treasury saidd: "Our message is clear - if you have a round one pound coin sitting at home or in your wallet, you need to spend it or return it to your bank before 15 October."

What will happen to the old coins?

Coins sent to the Royal Mint will be melted and used to produce the new £1 coin. However, given the amount of counterfeit old £1 coins in circulation, not all those received by the Royal Mint are likely to be recycled.

A survey undertaken in May 2015 found that the rate of counterfeit UK £1 coins in circulation was 2.55%. While the rate was lower than the 3.03% recorded a year earlier, it still meant approximately one in 50 £1 coins was phoney.

The Royal Mint has recently said that, to the best of its knowledge, no new £1 coins have so far been forged.

"It's been designed to be fit for the future, using security features that aim to safeguard our currency, and currencies around the world, for years to come," said Royal Mint chief executive Adam Lawrence.

What has changed since the old £1 coin was introduced?

Quite a lot, actually. When it was introduced in 1983, you could get a pint and a loaf of bread for with just over one of those shiny new coins. These days, you would need four new £1 coins to complete that particular purchase.

After all a pound is still a pound. However, when one looks at what a pound will buy you, it reveals the striking impact of inflation.

"Some prices have risen faster than others, so while the price of a pint of milk has more than doubled, the price of a loaf of bread has almost tripled and the price of a pint of beer has risen more than four-fold," said Sarah Coles from Hargreaves Lansdown.

"This has had a dramatic effect on your personal finances, and highlights why it's vital to protect yourself from the effects of inflation."

(Sources: The AA, Office for National Statistics, Post Office)