UK Prime Minister Boris Johnson's decision to suspend parliament later this month until shortly before Britain leaves the European Union is lawful, a Scottish court ruled on Wednesday, saying the matter was not one for judges to decide. 

More than 70 opposition lawmakers had challenged Johnson's right to suspend, or "prorogue" parliament, arguing it was illegal and unconstitutional because his intent was to force through a no-deal Brexit on October 31 by limiting the opportunity for opponents to object. 

Judge Raymond Doherty said the question was not a matter for judicial interference and was a political issue which should be judged by parliament and the electorate. He said it was up to parliament to decide when it sat. 

"In my opinion, there has been no contravention of the rule of law. Parliament is the master of its own proceedings, rules and privileges," Doherty told Scotland's Court of Session. 

"This is political territory and decision-making which cannot be measured against legal standards and only by political judgments," he added.

Joanna Cherry, a Scottish National Party lawmaker who led the challenge, said they would seek to appeal the decision. 

Johnson announced on August 28 that he would suspend parliament from mid-September to mid-October, shortly before Britain is due to exit the EU on October 31, so that his Conservative government could announce a new legislative program. 

The Scottish court was told on Tuesday that a memo passed to Johnson two weeks beforehand indicated he was looking to suspend parliament while his aides were publicly denying there were any such plans. 

The case is one of three legal bids to stop the prorogation. 

Businesswoman Gina Miller, who in 2017 successfully forced the government to get parliamentary approval before it formally issued Britain's divorce notice to the EU, is taking a challenge to London's High Court on Thursday, a case backed by former Conservative Prime Minister John Major. 

Another case is due to be heard in Northern Ireland on Friday.