A row has broken out at Westminster after parliamentary authorities banned the use of the word "separate" in a Commons debate on independence.
The move by House of Commons clerks in the wake of SNP protests prompted Labour to cancel a debate on the future of Royal Mail in Scotland.
Labour said it would attempt to reschedule the debate, tabled by its MP Iain McKenzie.
The SNP sees the word "separate" as pejorative.
A Commons spokesman said the change to the debate, which had been titled, "The Royal Mail in a separate Scotland", was made for procedural reasons, because independence was a "hypothetical" situation.
SNP MP Pete Wishart used the dispute, which comes before the 2014 independence referendum, to accuse Labour of "throwing a strop", while Labour said the SNP was trying to manufacture a row.
Mr McKenzie said he decided not to go ahead with the debate because the change was made at too short notice, adding: "What really happened here is what we've come to expect from the SNP, who have decided they would shut down all debate."
"They go into a tantrum and they think that they can avoid the real hard questions about what would happen after the 2014 referendum."
Perth and North Perthshire MP Mr Wishart told BBC Scotland: "The House of Commons authorities have made a ruling that the word separation is now no longer legitimate when it comes to describing this debate."
Mr Wishart said he now expected the House of Commons to review previous uses of the word, including in the Scottish Affairs Committee's inquiry into, "the referendum on separation for Scotland".
A Commons spokesman said: "Debates must refer to something which ministers can answer to.
"Independence is only a hypothetical situation and is not one covered by ministerial responsibility.
"That is why it was changed."