The ASA received one complaint for an E.On regional press ad that stated: "10 energy companies have gone bust in the last year... 70 years and still going strong...".
Given E.On was formed in 2000, the ASA received a complaint that questioned whether the claim "70 years and still going strong" was misleading.
In its defence to the challenge, the energy company said it was promoting interest in E.On as an energy supplier.
It also claimed it E.On claimed it could demonstrate that the supply of energy had been uninterrupted from 1947 until now.
After the utilities sector was nationalised in 1947, the Electricity Act of 1989 privatised the industry, naming East Midlands Electricity (EME) the successor to the board that supplied and distributed electricity throughout the 41 years it was nationalised.
EME was acquired and rebranded by Powergen in 1988 – the company E.On acquired in 2002.
It therefore argued that although the trading name of the company providing the supply had changed over the years, there had been a continued obligation to supply which it had continued to do.
In response, the ASA said consumers would understand the claim "70 years and still going strong" as a reference to E.On as a private company.
It also decided that the period of time when the electricity industry was nationalised should not count towards its trading period because, at this time, it did not exist as a private company.
The ASA concluded that the ad should not appear again in its current form.