Britain should use the opportunity presented by Brexit to bolster the capacities and powers of its regulators, White said in a speech on Thursday to the Institute for Government.

The formal two-year process for Britain to leave the European Union is due to be triggered by March 2017, the exit will require transferring all European laws which have an impact on the United Kingdom into a domestic framework.

"We have the opportunity to introduce a wider set of considerations in merger decisions, including policy or public-interest concerns where a company is deemed to have particular strategic significance for the UK," she said.

But she said any adoption of greater powers would not amount to "regulatory creep" or "new powers for the sake of it".

White also called for the introduction of new protections for consumers to prevent markets being uncompetitive, an argument she said the European Commission had failed to heed.

Telecoms has undergone further consolidation in recent years, with BT's purchase of mobile operator EE cleared by regulators, while Three's acquisition of O2 was blocked, leading to its owner Spanish Telefonica to seek a public listing for the mobile operator.

Investment bankers advising companies on M&A warn privately of increasing scrutiny over mergers and acquisitions driven by what they see as political motivated protectionism following the election of Donald Trump and Britain's vote to quit the EU.

Ofcom said on Tuesday it will go to the European Commission to try to force BT to legally separate Openreach, the division that supplies broadband to millions of homes and businesses, in a bid to spur investment in the country's ageing network.

(Reporting by Dasha Afanasieva; Editing by Alexander Smith)

Stocks treated in this article : Telefonica SA, Vodafone Group plc