An accountancy firm will celebrate its 40th anniversary next month.
THP Limited Chartered Accountants, based in High Street, Wanstead, was set up in 1974 and now has five offices around the area.
It offers help to businesses and wealth management for individuals.
A party is planned for July 10 at Wallace Collection Museum, in Hertford House, Marylebone, starting at 6.30pm.
Director of THP, Andy Green, said the firm's success on the high street was down to location, treatment of clients and moving with modern technology.
He said: “Our location in Wanstead is fantastic because it has a village feel to it, and people regularly pop in to have a chat to us, this is not normal for accountancy firms.
“The success we have had is due to 100% commitment to our clients, we become friends with them.
“We have a solid foundation of long-standing clients and this is very important to survive in the high street these days.
“It is also important to move with the times and embrace new technology, I believe every business, whether small or big, needs a strong website."
Since opening in Wanstead in 1974, the company has opened offices in the City of London near Monument Tube station, Cheam in Surrey, Chelmsford and in Saffron Walden in Essex.
Mr Green offered advice to fellow local businesses hoping to survive on the high street.
He said: “You see retail businesses in particular come and go in the high street.
“Small businesses need to have a solid plan in place to survive, they need big company disciplines to make sure they prosper.
"This is the best piece of advice I can offer, some make it up as they go along which is definitely not recommended."