HBO is groveling for mercy after airing a grisly scene starring the head of George W Bush.

The former president's noggin shows up shish-kabobbed on a barbarian's pike in a scene from the chainmail-and-boobs medieval fantasy series Game of Thrones.

Fans noted online that the show's creators had revealed their use of the 43rd president's coconut in the DVD commentary that accompanied the first series. Now HBO is scrambling to avoid the boiling oil of censure.

"We were deeply dismayed to see this and find it unacceptable, disrespectful and in very bad taste," the cable channel said in a statement. "We made this clear to the executive producers of the series who apologised immediately for this inadvertent, careless mistake. We are sorry this happened and will have it removed from any future DVD production."

Although the face of the head in question is not visible, the view being a partial profile from the rear, the shapes of the lips, nose and brow are a match with Bush.

The skewered skull appears to be contemplating the middle distance on a partly cloudy afternoon, lower lip tucked into upper. Tangled and bloodstained brown hair hangs past where the shoulders would be.

HBO's strong apology followed an earlier statement of contrition by the co-creators of Game of Thrones, David Benioff and DB Weiss. They admitted that the head was Bush's but said there was no political commentary intended.

"We use a lot of prosthetic body parts on the show: heads, arms, etc," the pair said in a statement. "We can't afford to have these all made from scratch, especially in scenes where we need a lot of them, so we rent them in bulk. … After the [Bush] scene was already shot, someone pointed out that one of the heads looked like George W Bush. … We meant no disrespect to the former president and apologise if anything we said or did suggested otherwise."

The scene appears in the season one finale of the hugely popular Game of Thrones series, which is now in production for a third season. Thrones is an adaptation of novelist George R R Martin's series A Song of Ice and Fire.