The company's new chief executive said the telecoms firm had become uncompetitive and 11,000 roles would go over the next three years.

The group employs just over 100,000 people globally, with just over 9,000 of them in the UK.

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Vodafone was yet to respond to requests for information on how many UK roles would be affected but it was confirmed that its headquarters, in Berkshire, would see an impact.

Margherita Della Valle, who was permanently appointed CEO last month after her predecessor Nick Read was ousted late last year, said: "Our performance has not been good enough.

"My priorities are customers, simplicity and growth. We will simplify our organisation, cutting out complexity to regain our competitiveness."

She was speaking as Vodafone reported a 1.3% drop in full-year earnings to £12.8bn.

That figure missed its own guidance.

The company forecast little or no growth in the same measure over the current financial year - with Germany, its biggest market, proving the major drag while Spain also struggled.

Growth in Africa and higher handset sales, however, enabled it to eek out a 0.3% rise in revenue over the 12 months.

There was no update on the proposed tie-up of its UK business with Hutchison's Three UK, with talks continuing.

Shares fell by 4% at the open.

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Matt Britzman, equity analyst at Hargreaves Lansdown, said of the company's update: "Lacklustre performance has been something markets have come to expect from Vodafone of late, and full-year results didn't buck the trend.

"Higher energy costs and continued weakness in Germany meant underlying cash profit came in below the recently downgraded company guidance.

"New CEO, Margherita Della Valle, has been very vocal about the host of challenges she's facing in her new role - the honesty is refreshing but not enough to keep shares from falling on the news."