Google Business Profile, in detail
The Google Business Profile (formerly Google My Business) is the primary asset that determines map pack ranking. It is a free Google product. Most restaurants have one. Most restaurants treat it as a "set and forget" listing, which is why most restaurants do not rank in the map pack.
The non-negotiables for a London restaurant Business Profile: complete every field, no exceptions. Pick the most specific primary category (Italian Restaurant, Tapas Bar, Steakhouse, Sushi Restaurant, not generic "Restaurant"). Add every cuisine type as a secondary category. Set hours accurately. Add holiday hours and any closures. Upload at least 50 photos covering the exterior, interior, dining room, bar, kitchen, key dishes, and the team.
Then keep it active. Post weekly: a new dish, a special, an event, a chef story, a customer moment. Respond to every review within 48 hours. Upload a few new photos every month. Update the menu link if the menu changes.
The single biggest unforced error London restaurants make is letting the Business Profile go stale. A profile that gets weekly posts will outrank a profile with the same review count but no recent activity. Recency is a strong ranking signal.