Scores of young people demanded to know what has happened to the jobs promised by Olympic chiefs, as they protested outside the 2012 media and broadcasting centre on Thursday afternoon.

Wearing sports shirts emblazoned with the slogan "don't leave us on the subs bench", 70 campaigners from The East London Citizens Organisation (TELCO) cut a cake with the number "40,000" iced on it at BT Sport's HQ at the Here East business hub.

The figure represents the number of jobs the park's guardian, the London Legacy Development Corporation, has predicted for the park and its surroundings by 2025.

They asked bosses at the TV channel to "share a slice" with them, and to keep the Olympic Legacy promise by providing them with paid work experience to help get them on the career ladder.

The 2012 Olympic Games cost the taxpayer £8.77billion and promises were made the huge project would generate thousands of jobs and homes.

But last year the Gazette reported that most of the 11,000 jobs promised for the Olympic Park have failed to materialise since 2012.

Oran Blackwood, the special educational needs co-ordinator from Elatt, a training school in Kingsland Road, told the crowd assembled outside Here East in Hackney Wick: "This park represents an important historical journey for British people and especially people living in London. I'm not just talking about the Olympics or the Diamond Jubilee for the Queen, but for the first time in history four of the most impoverished boroughs in London were drawn together with the hope of economic growth.

"Unfortunately, seven years later, I find myself asking the challenging question: 'Where is that economic growth for the people who live and work in Newham, Tower Hamlets, Waltham Forest and my borough Hackney?'"

He added: "We are hoping someone from BT will answer some of our questions and think about how corporations like BT Sport can help young people remove the glass ceiling they are facing."

Emmanuel Onapa, 19, a former BSix student preparing to attend Exeter University, told the crowd how his mother moved to the UK from Uganda in the 1970s.

He said: "I wasn't really privileged, and I see how people I grew up with didn't see opportunities and that led to a life of gangs. My mum told me that life is based on meritocracy, and if you work hard you will make it, but that is under threat because of companies like BT which lack an emphasis on meritocracy and are rather based on people's connections."

There were cheers when the march organisers were handed a letter signed by BT Sport head, Simon Green, which said the media giant was "very open to meeting".

BT Sport has run two apprenticeship programmes in the past four years with most participants coming from boroughs neighbouring the park.

It has also enabled 18 pupils to complete 12-week projects, and held four day-long bootcamps for 100 pupils at risk of leaving school without a job, training or college place.

The protesters say it's not enough and they need opportunities for more people. Courtney Sarrell, 16, who attends Elatt, told the Gazette afterwards he would love to work at BT.

"I'm interested in a media apprenticeship or a work placement, and I've trying to get one for a while," he said.

"I feel like they noticed we were there, and we have done our part, getting us out there to say we need more opportunities.

"They haven't kept the Olympic legacy promise and I do feel upset about that because they didn't follow through, so that's why we did this little movement.

"Now we've put ourselves out there to say: 'This is what we want,' I feel like they are obliged to make a change and open some opportunities for us." Paul Brickell, the LLDC's executive director of regeneration and community partnerships, said: "Following the 2012 Olympic and Paralympic Games there is a growing legacy of high quality jobs in the area.

"We work very closely with Here East and their tenants to ensure east Londoners are at the front of the queue for these jobs."

A BT Sport spokesperson said: "BT Sport has been extremely active in supporting the community and welcoming young people into the studio to learn more about the industry and career opportunities."

Gavin Poole, CEO of Here East, said: "We are committed to delivering the Olympic legacy."