Tesco, Britain's biggest retailer, said it is considering a trial of an upmarket convenience store under the 'Tesco finest' banner but has not disclosed when or where a pilot will be launched.

Tesco hosted a capital markets day for analysts and investors this week at which it presented a slide flagging an opportunity for a 'Tesco finest' store concept with a 7% operating margin.

This is significantly ahead of the group-wide target of 3.5% to 4%.

The premium 'finest' range of grocery products is Tesco's most expensive. 

"'Tesco finest' as a brand is one of the largest food brands in the country. We have a very high percentage of more upmarket customers," chief executive Dave Lewis said today. 

"The opportunity to curate that range and bring new things in a more convenient outlet is something that we have tested, is something we're interested in," he added. 

But Lewis said Tesco is: "Not at a place where we are saying we're going to open this shop or this many shops." 

The CEO said the point of the capital markets day was to share with investors a number of growth opportunities Tesco is actively looking at without giving specific details on timings. 

"No dates for any of the initiatives were given yesterday," he said. 

Last year Tesco launched the Jack's chain to compete with German-owned discounters Aldi and Lidl.

Other initiatives Tesco discussed include opportunities to sell more unique brands and online meal subscriptions, developing its Clubcard loyalty programme with a subscription model, setting-up mini fulfilment centres at the back of stores for online grocery, and delivery robots.

Celebrating its 100th year, Tesco is deep into a recovery plan under Lewis after a 2014 accounting scandal capped a dramatic downturn in its fortunes. 

He said in April Tesco had met, or would soon meet, most of the turnaround goals he set in 2016.

This included a key margin target of earning 3.5 to 4 pence of operating profit for every pound customers spend by the end of its 2019-20 financial year. 

Dave Lewis said today he did not issue a new margin target at the capital markets day. 

"We said there was more opportunity for us to lower cost and that gave us the opportunity to invest back in the customer offer (and) new propositions, or if none of those were available then the opportunity would be to improve margin," he told reporters.