Classic FM has obtained a leaked BBC document which it claims proves that the corporation is exploiting its TV channels to target the national commercial station.

The confidential document, called The BBC Network Radio Five Year Strategy Plan, outlines Radio 3’s marketing plans and has been shown to Marketing Week.

It states: “Radio 3 faces only one major competitor, Classic FM.” In another key phrase, the document continues: “Limited TV airtime available for trailing the radio networks should be prioritised against major events which gain Radio 3 credit for distinctiveness vs Classic FM (eg: The Proms).”

GWR, which owns Classic, complained to the Broadcasting Standards Commission in February about a trailer for Radio 3 that ran for two months on BBC2 early last year. The ad featured famous snippets from plays, and ended with the tagline which said that Radio 3 “gives you more than just the famous bits”.

GWR complained this was a direct attack on its station and an unfair use of advertising.

The document also goes on to state that from a “limited marketing investment” these ads gave the corporation an “opportunity to benefit from free BBC airtime”. The BSC ruled against the commercial radio group, saying any comparison made between the stations is “incidental”.

GWR chief executive Ralph Bernard has written again to the BSC accusing the BBC of “misleading” it. Bernard will also write to BBC chairman Sir Christopher Bland, asking him to explain why it told the BSC the Radio 3 campaign made no direct comparison between the two.

The full BSC adjudication will not be released until November 26. There is no right of appeal. The BSC will not comment on the report until then. But a spokeswoman for the BSC admits: “Further correspondence has been sent to us, which is being looked at.” She did not rule out a new inquiry.

A spokeswoman for the BBC says: “We are adamant that we have not misled the BSC in any way.”