Davies, who will leave the bank this summer after five years, takes on the new role of director of brand and communication at E.ON, where his responsibilities will include advertising, sponsorship, online, brand strategy, PR and internal communications.
He succeeds Gary Pepler, who has held the energy's company's top UK marketing role on an interim basis since the departure of Helen Merrick earlier this year, and will report directly to Paul Golby, chief executive of E.ON UK.
Davies said: 'It's a fantastic opportunity. We have grown up in a time when energy has been in plentiful supply and we are now entering an era where that is not the case anymore. I think it is going to be a really interesting sector to be involved in.'
He is to be succeeded at Abbey by Keith Moore, currently head of communications planning and sponsorship.
Davies began his career at J Walter Thompson in 1990 and was founder and managing director of its digital brand consultancy. He departed for cable group NTL, where he rose to marketing director before joining Abbey in 2003.
In his five years at Abbey, he worked on two rebrands, and he leaves as the bank prepares to rebrand once again, taking the name of parent company Santander.