UK bookmaker William Hill has signed a five-year extension to continue as the title sponsor of the Professional Darts Corporation’s (PDC) World Darts Championship until at least 2020.

Last year was the first for William Hill as the tournament's title sponsors, with this year’s event set to kicks off at London's Alexandra Palace tomorrow.

The 2014/15 William Hill World Darts Championship featured an epic 13-set final between eventual winner Gary Anderson and the legendary Phil Taylor, but also broke records for viewing figures with its worldwide TV coverage.

Four million fans watched coverage through the dedicated Sky Sports Darts channel throughout the tournament, with the broadcaster again devoting a channel for the duration of this year's event.

“I’m delighted that we’ve extended our sponsorship agreement with the PDC for a further five years, as the William Hill World Darts Championship is now one of the highlights of the sporting calendar and one that takes centre stage over the festive period,” said William Hill CEO James Henderson.

A record 66,000 tickets have been sold for this year's £1.5m event, which runs until January 3rd. Having seen an additional £250,000 added to this year's prize fund, the tournament's prize fund will continue to grow through each year of the William Hill deal to over £2m in 2020, with £500,000 to the winner.

"William Hill have been great supporters of the PDC in recent years and it's fantastic that they will remain as title sponsors of the World Darts Championship for at least the next five years," said PDC chairman Barry Hearn.

"The tournament has gone from strength to strength in recent years, and with record ticket sales and a record prize fund, the forthcoming William Hill World Darts Championship promises to be the biggest and best ever.

"We look forward to working with William Hill over the coming years to continue that growth for our sport's greatest event."

Fans can also keep up with the action on the William Hill iOS darts app, which the operator claims is the only darts simulator to also offer real-time betting.

Using rapid roulette-style betting, customers on the updated William Hill darts iOS app can bet where the first dart of each visit will land, by simply placing casino chips on the dartboard.

The real-time darts app displays live statistics and enables customers to follow every match of the World Championships dart by dart.