The UK Government is hostile to devolution and there's "no trust" left between Holyrood and Westminster, MPs have been told.

Scotland's Constitution Secretary Michael Russell said the already-poor dialogue between the two leaderships has gotten "significantly worse since Boris Johnson became Prime Minister".

His comments came as he raised concerns about the UK Government's Internal Market Bill, which enters the committee stage in the Commons today, having been voted through despite major opposition.

Russell told the Committee on the Future Relationship with the European Union: "There is, in my view, a hostility to devolution in the current government."

He went on: "We have been in such a difficult set of circumstances for so long that it would be difficult to find a way in which we could work constructively together.

"There is no trust in the relationship, absolutely none now."

The SNP MSP said the Internal Market Bill could allow a US company to take legal action to "force its way" into Scotland's NHS and permit the UK Government to spend money directly in devolved areas.

While senior Tories raised deep misgivings after ministers last week admitted the Bill breached international law, on Monday evening MPs voted to give it a second reading.

The Scottish and Welsh Governments fear the impact the Bill will have on devolution across the UK, with both branding it a "power grab".

That's in contrast to comments from Cabinet Office minster Michael Gove, who has repeatedly described it as a "power surge" which will hand more powers to the devolved governments.

Speaking from his Argyll home, Russell said: "I'm very familiar with power surges.

"We have problems with the electricity supply here in Argyll all the time.

"Power surges tend to knock things out and wreck things rather than actually contribute positively."

Jeremy Miles, the Minister for European Transition in the Welsh Government, said the Bill "enhances" the number of areas where powers were reserved to London and provides for ministers there to have spending powers in devolved areas.

He told the committee: "I have heard the argument repeatedly made that the Bill enhances the devolution settlement.

"I don't accept that for a second and I haven't had anybody point me to a section where those powers are conferred."

Russell said teh Bill has "undercut" the existing devolution settlement and called it "sneaky in another way", saying it could allow for the actions of the devolved governments to be "overridden by the whim of the UK Secretary of State".

Scotland's Constitution Secretary said: "What is here is undoubtedly, without a shadow of doubt, an enormous assault on the devolved powers."

He told MPs he believes under the legislation "all public services could be opened up to a variety of tenders and influence which the current Scottish Government would not wish".

Russell suggested voluntary frameworks could have been used instead of the legislation, which sets out processes for smooth trading to continue between the four nations of the UK when the Brexit transition period finishes at the end of December.

Miles said that, as far as the Welsh leadership is concerned, "engagement with us a government was significantly better" when Theresa May was in Downing Street.

He told the committee: "We think that much closer working is necessary at this point, given how much closer we are to the end of the transition period."