SpaceX and its Starlink satellite network have made headlines dangling a vision of free emergency service coverage direct to all mobile devices, undoubtedly connected to its ongoing battles for FCC approval.
Starlink is the clear leader in the D2D space and almost certainly will be the first to launch its service. AST Space Mobile, backed by various mobile operators (including Vodafone) is lagging significantly behind, having not yet launched any commercial satellites.
The UK is however a relatively unfavourable geography for D2D, due to its high latitude and relative density, and we don't expect any launch of commercial service in the UK by Starlink or AST Space Mobile before 2026.