A Downing Street spokesperson said:
The Prime Minister called President Erdogan of Turkey this evening to express his condolences following today’s terrorist attack in Istanbul. They agreed on the importance of remaining resolute in fighting terrorism, and President Erdogan updated the Prime Minister on the investigation. The Prime Minister offered the UK’s support in establishing who was responsible for the attack.
Noting the vital work that Turkey and others in the region are doing to support refugees from the Syria conflict, they discussed the upcoming London Syria Conference and agreed to work closely together to ensure its success.