Tesco has three stores in Inverness including one in Tomnahurich Street

The market dominance of supermarkets Tesco, Asda, Sainsbury's and Morrisons is to be examined for the third time in seven years.

Lib Dem MP Danny Alexander raised fears over about the impact of Tesco's three stores on other shops in Inverness.

The Office of Fair Trading confirmed the probe on Tuesday.

Mr Alexander said: "I am pleased that the OFT has decided to go ahead with a Competition Commission inquiry into the grocery market.

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"It is good to see that the OFT, in its decision, makes specific reference to the issue of concentration of supermarket power in local markets such as Inverness."

He added: "I will be writing to the Competition Commission to highlight directly the concerns of people in Inverness, and I hope that the inquiry will be able to take a detailed look at the situation here."

A recent survey indicated that Tesco had a 51% share of the market for groceries in Inverness, the highest rate of penetration for any locality in the UK.

Sir Terry Leahy, Tesco chief executive, said customers have a choice where they shop.

He said: "But we also know that some people have concerns and this inquiry gives us an opportunity to listen to those and address some of the myths surrounding our industry.