Heathrow has a variety of meet-and-greet services, which I discovered recently when making travel arrangements for an elderly relative. Some (but not all) will meet you at the jetbridge and escort you through the normal channels, so it's helpful for someone who wants assistance, but it doesn't necessarily save any time. There is also a service as tennessetom mentions which skips the terminal entirely, takes care of immigration in a private suite, and collects your luggage. So you can choose what you like depending on your budget. Will post links below in case the information is helpful for readers in the future:

Meet and Assist at Heathrow (LHR's official website)
Heathrow VIP