A Downing Street spokesperson said:
This afternoon the Prime Minister spoke to Prime Minister Rajoy of Spain. The Prime Minister expressed her condolences over the loss of life and the damage caused by the forest fires in northern Spain.
The two leaders discussed the ongoing situation in Catalonia. The Prime Minister reiterated that the UK is clear that the referendum had no legal basis and that any unilateral declaration of independence would be inconsistent with the rule of law. She added that the UK would not recognise any such declaration of independence by Catalonia.
On Brexit, the Prime Minister and Prime Minister Rajoy discussed progress in the negotiations and looked ahead to meeting at this week’s European Council.
Link: Press release: PM call with Prime Minister Rajoy: 17 Oct 2017
Source: Gov Press Releases