London, Jan 26 : The UK's Competition and Markets Authority (CMA) on Friday launched a formal probe into the proposed $19 billion merger between Vodafone and CK Hutchison-owned Three UK.

The CMA now has up to 40 working days to assess the deal as part of a Phase 1 investigation.

The regulator said that the review is designed to identify whether the deal may lead to a 'substantial lessening of competition' and ' if so ' whether a more in-depth Phase 2 investigation is required.

'This deal would bring together two of the major players in the U.K. telecommunications market, which is critical to millions of everyday customers, businesses and the wider economy,' CMA chief executive Sarah Cardell said in a statement.

'The CMA will assess how this tie-up between rival networks could impact competition before deciding next steps,' she added.

The regulator is inviting views by February 9 on how the merger could affect competition. The statutory deadline for this investigation is March 22.

'If the CMA finds the merger could lead to a substantial lessening of competition, then it can refer it for a more in-depth Phase 2 merger investigation. Phase 2 investigations last between 24 and 32 weeks and are led by an independent panel of experts,' said the regulator.

In June last year, Vodafone and CK Hutchison entered into binding agreements to merge Vodafone UK and Three UK, with the former holding a 51 per cent stake and CK Hutchison 49 per cent.

/IANS