The Eastern Daily Press is one of Archant's 50 titles

On Thursday, the Office of Fair Trading said it had asked the Competition Commission to investigate the takeover of the mostly London and Essex titles.

Archant, which owns local newspapers across Norfolk, Suffolk, Hertfordshire and Cambridgeshire, bought the papers from Independent News and Media.

Archant said it was certain the sale was in the interests of competition.

The Office of Fair Trading (OFT) said it had decided to refer the completed acquisition by Archant of the London Regionals division of Independent News & Media (IN&M) to the Competition Commission.

We believe the Competition Commission needs to look at this merger in greater depth Vincent Smith, the OFT's director of competition enforcement

Norwich-based Archant bought the weekly newspapers from IN&M in two separate deals worth up to �62m in December.

The titles included the Islington Gazette, the East London Advertiser, the Barking & Dagenham Post and the Kentish Times series.

The OFT said in a statement on Thursday that it believed the takeover would result in a "substantial lessening of competition within the markets for free and paid for local newspapers in various parts of north and east London".

Interests of competition

Vincent Smith, the OFT's director of competition enforcement, said: "We believe the Competition Commission needs to look at this merger in greater depth."

IN&M said in a statement that Archant had assumed responsibility for any further regulatory review at the time of the unconditional transfer of the titles in December

A statement from Archant said the group remained convinced that the acquisition was in the interests of competition.

"We will be reviewing the OFT's decision and analysis and will be working to satisfy the Competition Commission of the pro-competitive nature of this transaction." it said.

The commission is expected to report its findings by 14 October.

'Strong portfolio of newspapers'

Archant's plans to buy the titles were first announced in December last year.

The news came not long after Archant announced cost-cutting redundancies among editorial and photographic staff at its Ipswich-based East Anglian Daily Times and the Evening Star.

In December, John Fry, chief executive of Archant, said: "Archant is acquiring a strong portfolio of local newspapers that all play an important role in their local communities.

"This will strengthen our position as the UK's leading independently-owned community media publisher."

Archant currently produces four daily regional newspapers, including the Eastern Daily Press in Norwich and the East Anglian Daily Times in Ipswich.

It has more than 50 weekly newspapers, including titles such as the Royston Crow, the Ely Standard and the North Essex Advertiser, with a combined circulation of around 2.5 million copies every week.