Tens of thousands of members of the Salvation Army are descending on London to mark its 150th anniversary.

The movement began in East London in 1865 and was the idea of William and Catherine Booth who took the word of God to the city streets, and helped some of Britain's poorest people.

The Salvation Army says its founder, Mr Booth, was told by his son about all the homeless people sleeping on the banks of the Thames.

His response was simple: "Go and do something."

This week the organisation is celebrating by welcoming members from all over the world including Kenya, Latvia and India back to London.

It is hosting a series of events at the O2 arena.

Jennifer:I'm rly lucky2b prt of Kuwait Salvation Army:the ppl&atmosphere when we're together,is gr8! @Boundless2015 pic.twitter.com/2FMetw16VJ

— Claire (@salvoclur152) June 30, 2015

The Mizo Singers from India Eastern are ready for @Boundless2015 ! We're on our way! #Boundless2015 #beboundless pic.twitter.com/2RBf1pBHkg

— Callum McKenna (@callummckenna) June 30, 2015

General Andre Cox, the Salvation Army's leader, told Premier they will be giving out more than 20-thousand doughnuts at the events: "That's basically from our history in the Second World War, when a lot of our American Salvation Army women were manning tea trucks for the troops and handing out doughnuts, and that's captured the imagination of a company here in the UK."

He added that everyone was looking forward to the events taking place over the weekend: "It will culminate on Sunday with a big march up the Mall to Buckingham Palace.

"We'll have several of our bands out there and people from all over the world in national costume, in our different uniforms.

"There's an evening where we'll get a flavour of the international army, with groups from all over the world - I love brass music so I won't get enough of that!"

Speaking to Premier he stressed there would be challenges ahead: "We've got huge challenges all around the world, of different challenges and nature really.

"In the West we're faced with materialism, secularism, the world seems to want to impose it's will particularly on people of faith.

"In the 'third world' it's a lot more basic, there's this never-ending cycle of poverty and lack of finaces, so there are huge challenges as we go ahead."

#Boundless2015 delegates are still arriving in droves. Well, mainly planes. This group is from #Taiwan. Welcome! pic.twitter.com/GDiJVBpFCp

— David Giles (@DavidPGiles) June 30, 2015

Jambo! #Boundless2015 delegates from #Rwanda, #Burundi and #Uganda excited to be in London pic.twitter.com/BoB05LUXtZ

— David Giles (@DavidPGiles) June 30, 2015

Listen to Premier's Anna Cookson speak to General Andre Cox here:

You can listen to the whole interview here.