The Rugby Football Union has expressed its dismay that an advertisement celebrating England winning the grand slam has been leaked.

The video, produced by their official kit supplier Nike, shows several players, among them Toby Flood, Chris Ashton and Ben Foden, in a series of action clips. Signing off the advert that has been widely circulated on the internet is an image of England's red rose emblem on top of a caption reading 'Grand slam champions 2011'.

The video's release is highly embarrassing for the RFU after Martin Johnson's side were demolished 24-8 by Ireland on Saturday, ending their hopes of completing a first championship clean sweep since 2003.

The photo shoot for the footage took place midway through the Six Nations, which England won despite their defeat in Dublin. The RFU explained that filming the advert in advance was necessary for commercial reasons and has denied Ireland were taken too lightly.

A statement read: "The RFU works with all its commercial partners on their sponsorship activation. Forward planning is a crucial part of all commercial partnerships and all contingencies, winning or losing, have to be considered. It is disappointing that details of Nike's internal planning has got into the public domain.

"In no way did the RFU or the England team underestimate the challenge that the Ireland team would pose. We were well beaten by a team who played better and we have the utmost respect for [the Ireland coach] Declan Kidney and the Irish players."