Income taxes, Tax Years Subject to Examination (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Examination by Tax Jurisdiction [Abstract]
Provision for uncertain tax positions	$ 0	$ 0
United Kingdom [Member] | Earliest Tax Year [Member]
Examination by Tax Jurisdiction [Abstract]
Open tax years based on originally files returns	2021
United Kingdom [Member] | Latest Tax Year [Member]
Examination by Tax Jurisdiction [Abstract]
Open tax years based on originally files returns	2022
United States [Member] | Earliest Tax Year [Member]
Examination by Tax Jurisdiction [Abstract]
Open tax years based on originally files returns	2020
United States [Member] | Latest Tax Year [Member]
Examination by Tax Jurisdiction [Abstract]
Open tax years based on originally files returns	2022