Weary commuters heading for Pret A Manger could be in for a free coffee if a member of staff likes the look of them.

Instead of a loyalty card, Pret runs a behind the scenes system giving staff the opportunity to hand out free coffees to their favourite or most loyal customers.

The fast food and drinks chain has reason to cheer today as annual sales for the period to 1 January were up by 16 per cent to £594million.

Have you had a free coffee yet? Instead of a loyalty card, Pret runs a system giving staff the opportunity to hand out free coffees to their favourite or most loyal customers

Pret's boss Clive Schlee told the Evening Standard: 'We looked at loyalty cards but we didn’t want to spend all that money building up some complicated Clubcard-style analysis.

'Instead the staff have to give away a certain number of hot drinks and food every week.

'They will decide "I like the person on the bicycle" or "I like the guy in that tie" or "I fancy that girl or that boy".

'It means 28 per cent of people have had something free. It’s a nice, different way of doing it.'

Today, Pret unveiled an impressive set of annual results, with pre-tax profits rising by 14 per cent to £76million.

Since launching last October, Pret's macaroni cheese has proved particularly popular with customers, with the chain now selling 50,000 portions a week.

Sales of macaroni cheese now outstrip those of Pret's classic chicken and avocado sandwich.

The launch of other new products including quinoa rice pots has contributed 12 per cent to group revenues, Pret said.

The firm said coffee selling remains an 'area of growth', despite having sold an average of 1million cups a week last year.

While efforts to expand its hot food range continue, Pret's biggest selling item is still the banana, followed by porridge. The tuna sandwich has been pipped to the top sandwich post, having been overtaken by the chicken caesar baguette.

Rewarding loyalty: Pret's boss Clive Schlee (pictured) told the Evening Standard: 'We looked at loyalty cards but we didn’t want to spend all that money building up some complicated Clubcard-style analysis

Over the past year, the chain opened a number of new stores across the UK and abroad. Fifteen of 23 new stores Pret opened in the UK in 2014 were in London.

The group said it updated over 40 stores and extended six more last year, primarily to increase seating and reduce bottlenecks. It said it has spent £191million improving its stores over the last five years.

As Pret doesn't keep its sandwiches overnight for use the next day, the group also distributed over 3million sandwiches and salads to homeless charities last year.

The group said it was 'confident' about its prospects this year, and plans to build more shops in all of its international markets.

Pret's boss Clive Schlee said: 'These are a strong set of results and represent another successful year for Pret.

'With double digit growth achieved in virtually all of our markets, we continued our measured expansion of the business by remaining faithful to our core values and by responding to customer demand for innovative, healthy and hot food.'

Mr Schlee has made no secret of the fact he intends to make Pret as big as rivals Starbucks and McDonald's.

Ambitions: Pret A Manger boss Clive Schlee has made no secret of the fact he intends to make Pret as big as rivals Starbucks and McDonald's

He told the Evening Standard: 'We’d like to be a successful British global company – one that is really successful in different continents and that would be a very worthy goal.

'There’s only been five or six companies over the years that have managed that and most of them have been US companies. British ones have never really made it.

'We’re going to do it bit by bit and quite cautiously. Starbucks has been around for 70 years, so you can’t do this in one generation.'

The group has not always enjoyed such rosy results as those unveiled today. In 2013, accounts filed for Pret's parent company PAM Group revealed that turnover for the year to 2 January 2014 increased by 15 per cent to £509.9million, giving the group an operating profit of £40.1million.

But, Pret failed to make a profit as the private equity-owned firm had bank debts of £272million, which required interest payments of £13million.

With other costs, this meant PAM Group recorded a £33.4million pre-tax loss, more than its £25.1million loss in 2012.