With three young children and a full-time job, Emma Martini has little time for computer games. But every night she sits quietly at the end of her son's bed to reassure him while he falls asleep -- and plays Candy Crush.

"It stops me sitting there in the dark for 15 minutes staring at the wall!" the 32-year-old told AFP, laughing.

Martini is one of the legion of fans of the addictive online game, many of whom can be seen playing it at every spare minute on their tablets and smartphones.

Unlike conventional console games that can take hours, Candy Crush Saga is one of the most popular of the new "casual games" that can be played in short bursts and on the move.

It has seeped into every day life -- and attracted new audiences, with women making up two-thirds of Candy Crush players, according to its British developer King.

"I'm not into computers and what little time I've got I'm inclined to spend reading a book," said Martini, a teaching assistant from Spilsby in eastern England.

But she was persuaded to download Candy Crush by her mother, 52, who was "driving me crackers" sending requests to join the game on Facebook and help her pass the next level.

Now Martini plays every evening as her four-year-old dozes off, saying: "I'm filling a void of time."

"Casual gaming has really taken off in the female population," said Mark Griffiths, director of the International Gaming Research Unit at Nottingham Trent University.

"Most of it is fitting in between the baby having a sleep, or on the commute on the way home, but it's not something that takes over from the important things in your life.

"It's there as a quick fix for boredom."

- '100 percent concentration' -

Candy Crush is a simple game. There are hundreds of levels but they all involve moving brightly coloured sweets around a grid to get three of a kind in a row.

Yet it is utterly absorbing, causing travellers to miss their stop, workers to over-run their lunch hours and kids to stay up late into the night trying to get to the next level.

A gaming expert, Griffiths is a fan of traditional consoles but he plays Candy Crush on long journeys to distract himself from the pain of a long-term spinal problem.

"It's a game that requires 100 percent concentration -- you basically forget about everything around you," he told AFP.

Sophie Clayton, a 23-year-old from London who works for a jewellery company, says she is most definitely "not a gamer" but plays Candy Crush as "a boredom killer", mainly on her commute into work.

"I suppose the game is simple, unlike other electronic games. Although my sister thinks I'm an idiot for playing, especially when I'm stuck on a level," Clayton told AFP.

Candy Crush is free but players can pay for extras to help them move forward, a feature which nets King $850,000 (620,000 euros) in daily sales, according to the IDATE consultancy firm.

While a few people may find themselves racking up huge bills, experts say so-called "freemium" games depend on lots of people paying just a little.

Candy Crush records 700 million sessions a day, making it King's most successful product and driving the company's pursuit of a listing on the New York Stock Exchange.

For people like Tom, a 22-year-old engineer from London, the payment feature adds another challenge to the game -- to play it as much as they can without forking out a penny.

Players are given five chances to pass a level, after which they must wait for 24 hours or pay a small amount -- about $1 -- to buy back into the game immediately.

But if you set the clock on your smartphone a day ahead, the game thinks the time has passed, Tom explains.

"I did this so many times that on a Monday morning my phone clock thought it was Saturday. My alarm didn't go off and I was late for work," he admitted sheepishly.