A computer failure has caused chaos for punters wanting to buy tickets for tonight's £15m National Lottery rollover jackpot.

Ticket-selling terminals in 42 shops across Brighton and Hove have been out of action since Sunday.

Lotto operators Camelot admitted today they do not know when the power will be switched back on.

Terminals have been down since Sunday afternoon meaning shop assistants could not process any Lotto ticket sales.

The confusion has cost Camelot thousands of pounds in unsold tickets and denied many people a shot at tonight's big windfall.

Mukesh Patel, of Jalaram newsagent's, in St George's Road, Kemp Town, Brighton, said: "We'd expect to sell about 1,000 a day, and more today when there's a £15m jackpot.

"Instead we're having to turn people away when they've come in wanting tickets. They've been desperate for tickets but nearly everywhere has the same problem."

Yagnash Patel, who owns a shop in St James's Street, Kemp Town, said: "Today should have been one of our busiest days for a long time.

"It's very frustrating to explain to everyone the systems are down, especially as Camelot told us we may to have to wait until Friday."

An assistant at Greens newsagent in Leybourne Parade, Bevendean, Brighton, said: "We've had lots of people coming in who think we're to blame.

"This is costing Camelot a lot of money and it's causing us a lot of upset. People in Brighton are missing out on their chance for the £15m."

Sonia Karpozis, duty manager at Safeway in St James's Street said their terminals went down yesterday.

She said: "Because it's a rollover this week, we were expecting to sell a lot more tickets. But we've had to keep telling people the system is out of order."

The Sainsburys store in Lewes Road, Brighton, has also been affected.

The problem centres on two broken distribution nodes in a Brighton shop recently sold to new owners without Camelot being told.

Engineers have been unable to get access to the property until today to fix the connections.

A Camelot spokeswoman said: "We hope to get the system up and running again as soon as possible but I can't guarantee when that will be.

"We apologise to players and retailers for any inconvenience caused."

She said the failure did not affect all shops offering Lotto tickets in the city but was unable to say how many there were.

Staff at the Asda superstore in Hollingbury and W H Smith in Churchill Square, Brighton, said they had not experienced any problems.

Anyone wanting information about their nearest available Lotto outlet can call a Camelot helpline on 0845 910 0000.