The European Commission said it would decide by Oct. 16 whether to clear the deal, which would make Hutchison's Three UK business the second-biggest of the UK’s three remaining network operators.

The EU competition authority could either clear the deal with or without conditions or open an extensive investigation if it has serious concerns.

Hutchison could face a strong regulatory headwind after European Competition Commissioner Margrethe Vestager earlier on Friday said she was ready to veto a plan by TeliaSonera and Telenor to combine forces in Denmark because they had not offered sufficient concessions.

Hutchison, owned by Asia's richest man, Li Ka-shing, however is no stranger to tough regulatory demands. It was forced to offer significant concessions to secure the EU go-ahead for recent deals in Austria and Ireland.

(Reporting by Foo Yun Chee; editing by Andrew Roche)

Stocks treated in this article : Telefonica SA, CK Hutchison Holdings Ltd