Bath Rugby have issued a lengthy statement about the reasons behind their decision to prevent Leinster distributing 1,500 flags to travelling supporters last Saturday.
They say that new safety regulations introduced in the UK on November 1 mean that fans' flags must meet new criteria, including proof that the flags are fire-retardant.
They say the Leinster flags failed all three tests: a snap test, a slip test and a fire test.
Bath Rugby’s independent safety officer made the decision.
Bath distributed flags from the same supplier, but a different model, to their home supporters. These comply with the new regulations, they say.
They did not stop individual supporters bringing in Leinster flags.
"Whilst we understand that flags present a low risk of injury, we cannot and will not ignore the guidance that we are mandated to as part of our safety certificate," said Alex Cohen, Operations Director for Bath Rugby.
Leinster have insisted their flags are “covered by a safety certificate and that the same batch of flags are still in use”.
Bath have provided a fire certificate for their flags to Leinster ahead of the return fixture at the Aviva Stadium on Saturday.
Cohen wants supporters to return these flags to their ‘Elf and Safety’ team, who will recycle them and donate presents to the Temple Street Children's University Hospital in Dublin and The Royal United Hospital in Bath.
"We hope that whilst we are all here, talking about this topic, that we can change the conversation and actually do something that will make a difference at this time of year," he said.
"We will be collecting flags after Saturday’s game and will be donating to the local children’s hospitals for all of those children that couldn't make it to the Rec or the Aviva stadium and also might not be at home this Christmas."
They've also invited Leinster to participate in this flag collection on Saturday.