An advert in which Rangers described itself as the "most successful" club in Scotland, prompting complaints to the advertising watchdog, is to be reviewed by the body.

The move follows the intervention of a retired top civil servant who is now a senior Advertising Standards Authority executive.

If the review concludes the advert is misleading, Rangers may be forced to stop describing itself as the most successful club in Scotland. The advert had initially been cleared by the ASA after there were 78 complaints about ads which said: "Join Scotland's most successful club at Ibrox (stadium)" as part of a promotion on season tickets.

Complainants said the "most successful club" claim was misleading because it had only been formed last year, when Charles Green's Sevco consortium bought the assets for £5.5million.

But Sir Hayden Phillips, the retired top civil servant who acts as independent reviewer of ASA adjudications said there were flaws in the way the decision was made, which is being reviewed.

Sir Hayden questioned the ASA's assumption that the club and the newco headed by Charles Green which bought its assets last summer were separate entities.

Defending the ad, Rangers said previous owner-operator The Rangers Football Club Plc, named as oldco, went into administration in 2012, but the business and assets were bought by another corporate entity, known as the newco.

The club provided an extract from a decision by an independent commission appointed by the Scottish Premier League (SPL), which said "a club is treated as a recognisable entity which is capable of being owned and operated and which continues in existence despite its transfer to another owner and operator".

It also provided a letter from the European Club Association (ECA) concerning its continuing membership after the liquidation, which stated that, although run by a different legal entity, it considered RFC was still the same football club. But Sir Hayden told complainants that there had been a "procedural flaw" in that the ASA relied on an "extract only" of a report sent to it by the advertiser.

He said there was "also the risk of a substantial flaw of adjudication in the distinction that had been made between 'club' and 'company', especially in the light of previous ASA decisions about companies that change hands and the circumstances in which the new company could or could not trade off the reputation of the old company".

He added: "I recommended that in these circumstances the investigation should be reopened."

The ASA confirmed that Rangers could carry on describing itself as the "most successful" club in Scotland until the review had reached a conclusion.

"This does mean that the original decision could potentially be overturned," an ASA spokesman said.

A Rangers spokesman said: "We would like to reiterate once again that (to say it is a new club) is a ridiculous claim."