What does a triangle showing two elderly people mean?
Frail or disabled pedestrians are likely to cross the road ahead.

A red-bordered triangle showing two elderly people, one with a stick.
What you must do
Slow down and give people plenty of time to cross, as they may move slowly.
Where you will see it
Near care homes, sheltered housing and day centres.
Test yourself
The theory test asks you to recognise signs like this one. Try the road and traffic signs short test (with an easy and a hard set), or read the signs revision notes. Source: Know Your Traffic Signs.
Other common road signs
Meaning based on Know Your Traffic Signs and The Highway Code. The sign image is an official Department for Transport sign (Crown copyright) from Wikimedia Commons, reused under the Open Government Licence or the public domain. Always check the current Highway Code on gov.uk. Not affiliated with or endorsed by the DVSA.