A deal between the Conservatives and the DUP could pose a constitutional threat to the UK, according to the Scottish Liberal Democrats.

The party's leader Willie Rennie said taking sides in the politics of Northern Ireland could have "significant ramifications" for the rest of the UK.

Four Scottish Liberal Democrat MPs were returned after the election on Thursday and Rennie is due to meet the group on their first day at Westminster later on Monday.

Downing Street is in talks with the DUP over an agreement which would hand the Tories a working majority in parliament through a "confidence and supply" arrangement.

The deal is yet to be finalised, however, with the Northern Irish party's leader Arlene Foster due to meet Prime Minister Theresa May on Tuesday.

Rennie said: "Theresa May's decision to grasp on to the DUP reveals the depth of her desperation to cling on to power and the fundamental weakness of her position.

"Taking sides in the precarious politics of Northern Ireland could have significant ramifications for the whole of the UK, including Scotland.

"The UK Government should be operating as an honest broker in Northern Ireland but that is impossible if it is in hoc to one of the protagonists."

He continued: "The constitutional politics of the UK are closely intertwined with instability in one part directly impacting on other parts.

"We all work hard to deal with the issues that arise but that job will be made so much more difficult with this DUP-Conservative arrangement.

"There is rightly anxiety about the DUPs views on abortion and gay rights and these views must not have an impact on government policy."

He concluded: "Yet it is the constitutional threat that could have even wider and more immediate consequences.

"This is why Theresa May should abandon her embryonic alliance with the DUP before it does real and lasting damage."

Scottish Conservative leader Ruth Davidson has sought assurances from the Prime Minister that any deal with the DUP would not damage LGBT rights in the rest of the UK.