The company has already outbid its rivals in buying airwaves for superfast mobile broadband, spending some 802 million pounds in the regulator Ofcom's auction of radio spectrum in February.
Operators in Britain, and the rest of Europe, are making a big bet on faster networks in the hope that increased data consumption will boost falling revenues.
Vodafone, which launched Spain's first 4G service last week, said it was spending more than 2.5 million pounds a day this year upgrading its British network. Services are due to start later in the summer.
The additional spending this year will also go on integrating the fixed line network in Britain which it acquired through the acquisition of Cable & Wireless Worldwide (CWW) last year.
It said in September that it would take 18 months to two years and cost about 500 million pounds to fix years of under investment in CWW's network and customer service.
EE, the leader in the British mobile market, started rolling out Britain's first 4G network last year. It attracted 318,000 subscribers in the first five months.