The British government was back at the country’s Supreme Court on Wednesday, arguing that Prime Minister Boris Johnson’s decision to suspend Parliament for five weeks just before the country is set to leave the European Union was neither improper nor illegal.

But the justices pushed back on the second day of the historic legal showdown, which pits the powers of Britain’s legislature against those of its executive as the country’s scheduled Brexit date of October 31 looms over its political landscape and its economy.

The government’s lawyer, James Eadie, conceded that Johnson and his top officials had not made legally binding statements, but said other documents, including Cabinet minutes, had been submitted to the court.

Johnson sent lawmakers home on September 9 until October 14, which is barely two weeks before Britain’s October 31 departure from the EU. He claims the shutdown was a routine measure to enable his Conservative government to launch a fresh legislative agenda and was not related to Brexit.

Eadie argued that the decision to shut down Parliament was “inherently and fundamentally political in nature.” He said if the court intervened it would violate the “fundamental constitutional principle” of the separation of powers between courts and the government.

The government’s opponents argue that Johnson illegally shut down Parliament just weeks before the country is due to leave the 28-nation bloc for the “improper purpose” of dodging lawmakers’ scrutiny of his Brexit plans. They also accuse Johnson of misleading Queen Elizabeth II, whose formal approval was needed to suspend the legislature.

Aidan O’Neill, lawyer for a group of lawmakers challenging the government, said the suspension had “the intent and effect of preventing Parliament, impeding Parliament, from holding the government politically to account at a time when the government is taking decisions which will have constitutional and irreversible impacts on our country”. Eadie denied the prime minister was trying to prevent lawmakers from blocking his Brexit plans.

He said “Parliament has had, and has taken, the opportunity to legislate” against the government, and would have more time between October 14 and Brexit day.

But many economists and lawmakers believe a no-deal Brexit would be economically devastating and socially destabilising. Members of Parliament have put obstacles in Johnson’s way, including a law compelling the government to seek a delay to Brexit if it can’t get a divorce deal with the EU.