A delegation of MSPs is due to discuss Brexit legislation at the House of Lords in order to "avert a constitutional crisis".

Senior parliamentarians representing three Holyrood committees will set out cross-party concerns over the EU Withdrawal Bill on a visit to London.

They will attend the inter-parliamentary forum on Brexit, which brings together the relevant committees from both Houses of Parliament and the devolved legislatures.

It comes as the SNP slammed Scottish Conservative MPs for failing to "defend our national interest" by voting unanimously against amendments to the Bill in the Commons on Tuesday.

SNP Westminster leader Ian Blackford described the behaviour of the 13 Scottish Tory MPs as "utterly shocking" and said they had "promised Scots everything and delivered nothing".

A promise to introduce changes to the legislation's problematic clause 11 during report stage in the Commons failed to be met, with the amendments now expected to emerge in the Lords.

The UK and devolved administrations have been at odds for months on this key aspect of the Bill, which would result in EU responsibilities in devolved areas being temporarily transferred to Westminster.

The Scottish and Welsh Governments previously dubbed the Brexit legislation a "power grab" and have said they cannot recommend the devolved legislatures grant it consent in its current form.

The UK Government says the measure is necessary to avoid disruption of the UK's internal market and insists that it continues to make "good progress" in discussions with the Scottish Government.

Holyrood's cross-party finance and constitution committee has unanimously agreed that the current clause 11 is "incompatible" with the devolution settlement.

SNP MSP and committee convener Bruce Crawford said: "It is hard to overstate our concern, indeed dismay, that the UK Government did not amend the Bill during its Commons passage, despite a clear commitment to do so from UK ministers towards the end of 2017."

Also joining Crawford as a delegate is Conservative MSP Graham Simpson, convener of the delegated powers and law reform committee. They will be joined by the SNP convener of the Europe committee, Joan McAlpine MSP.

The other three in the delegation are the committees' deputy conveners Adam Tomkins of the Conservatives, the SNP's Stuart McMillan and Labour's Claire Baker.

A spokeswoman for the UK Government said: "We have made good progress in our discussions with the Scottish Government on common frameworks and we look forward to making significant further progress over the coming weeks."