Thousands of people have become the latest to find they were unlucky when they won the national lottery.

On Wednesday night, 4,082 players thought their luck was in after they selected five of the six winning numbers.

Their joy was short lived, however. The lottery organiser Camelot quickly broke the news that each had won just £15.

A week before, 36 people who had matched five numbers pocketed more than £1,700 each. Even those who matched four balls on Wednesday won £51 each.

The reason for the pitiful payout was that the numbers that the £15 winners had selected were incredibly popular, massively diluting the prize fund.

Many choose their lottery numbers with the help of the seven times table, it would appear. Five of the six main numbers drawn were multiples of seven — 7, 14, 21, 35 and 42, with the final number being 41. Lottery rules state that the prizes for matching two and three numbers are a fixed amount — a free Lucky Dip ticket and £25 respectively. Once this is paid out, the other prize tiers are allocated a percentage of the remaining pot: people who get four numbers receive 12.9 per cent; people who match five get 2 per cent and the jackpot winner gets 83.2 per cent.

A spokesman for Camelot said: “People clearly play ‘lucky seven’. More than 4,000 ‘match five’ winners is extraordinarily high, but it’s a lottery at the end of the day and the prizes people win are determined by the balls drawn and the number of people who match those numbers. As a result, extremely rare events like this do happen.”

This explanation did not, however, placate frustrated punters, who took to social media to express their frustration. “How bad does lotto get?” asked Harvey Cards on Twitter. “Five numbers pays £15 at odds of 144,000-1.”

Ben Webb added: “My mum got five numbers back in 1996 and won £5,299. I don’t even get this lotto now. I play only cos I have same numbers.” #Dontspenditallatonce was the unsympathetic hashtag of choice.

The unfortunate 4,000 are not alone, and can take comfort that in 1995 a jackpot of £16 million was shared between 133 people, all of whom had picked numbers from the central columns on the ticket. The payout of £120,300 each was the lowest for six correct numbers in lottery history.

Wednesday’s £15 payout was inauspicious timing for Camelot, which has come under fire in recent months for changing the format of the draw. In October, the lottery organiser added ten extra numbers, cutting dramatically the chances of winning the jackpot from about one in 14 million to about one in 45 million.

This increased the number of rollover jackpots but players have complained that it makes buying a ticket increasingly pointless.

In January, ten consecutive rollovers took the main Lotto prize fund to a record £42.2 million. Camelot says that the changes have increased ticket sales and therefore increased the amount of money given to good causes.

Making your own luck

Researchers at Southampton University have shown how choosing unpopular numbers significantly reduces the probability of sharing the top prize with others.

They found that the number 7 was the most popular, chosen 25 per cent more often than 46, the least popular.

The researchers recommend never choosing a sequence of numbers that others are also likely to choose, such as 1, 2, 3, 4, 5, 6. About 10,000 people choose that combination each week — so if it ever comes up, the jackpot will be massively diluted.

Punters should also avoid choosing numbers that form shapes across the ticket because many people opt for diagonal or symmetrical patterns.

It is also best to avoid numbers below 31, as these are frequently picked to match birthdays.