A surge in profits for online takeaway delivery group Just Eat failed to whet the appetite of investors as shares came under pressure.

It said its number of active users had risen by three million to 11 million over the first half of this year as revenues surged 54 per cent to £107.8 million compared to the same period in 2014, while pre-tax profits added 63 per cent to £14m.

But shares, which have climbed sharply since the group's stock market float last year, took a hit, falling as much as three per cent. One analyst pointed to the looming threat from rivals.

Today's figures showed hungry customers ordering food online via their mobile now represented 69 per cent of orders in the UK, the group's largest market - where revenues grew by half to £76.9m.

Just Eat makes money by connecting customers to more than 59,000 takeaway restaurants. However in the UK it said it had now started actively removing restaurants "that were giving consumers a consistently bad online experience".

The company has also been snapping up market-leading operations in Mexico, Australia and New Zealand and chief executive David Buttress said it would continue to look for "potential acquisition and partnership opportunities".

He added: "Just Eat has made a very strong start to 2015, increasing the numbers of active users, takeaway restaurants and orders.

"I am particularly pleased to see the results of our mobile strategy which has already created a much improved experience for our app and mobile users."

There was no dividend for the half year after an £18.2m pay-out last year as part of a reorganisation ahead of its stock market float. The company said it planned to retain earnings "to expand the growth and development of the business".

Shares have surged by nearly two-thirds since Just Eat made its market debut last April. Peel Hunt analyst Nick Batram said the strength of the stock price "allows no room for even the slightest disappointment".

He added: "In the near future, we see no reason why the positive momentum should not be maintained. However, the take-away food market is highly active with some big players entering the market globally."

Analysts have previously raised eyebrows over the £445m price tag for buying Australian rival Menulog.