Students have gathered outside a Conservative conference in London to protest at the scrapping of Education Maintenance Allowance (EMA).
The London Conservative Annual Conference was held at Hammersmith Town Hall.
London Mayor Boris Johnson and Transport Secretary Philip Hammond were due to speak at the event.
Protester James Mills said almost 100,000 London teenagers with families on low incomes relied on EMA.
He claimed up to 300 people took part in the protest while the Metropolitan Police said about 80 demonstrators were outside the Town Hall until about 1230 GMT.
EMAs were introduced by Labour to encourage young people from deprived backgrounds to stay in education and training after the age of 16.
Students whose parents' earnings fall below certain thresholds receive payments of £10, £20 or £30 a week.
Balance the books
Mr Mills, who is head of the Save EMA campaign and a researcher for the Labour MP John Robertson, accused Boris Johnson of only wanting to "speak to bankers" in the city.
"Boris Johnson and London Conservatives are letting this government pick the pockets of the poorest teenagers in our capital.
"There are over 60% of students on EMA at Hammersmith and West London College alone and over half of them are on the top rate of £30 a week," he added.
"If you go to William Morris College in Hammersmith you will find it is the same and that's before you even start at sixth form colleges in the borough."
The government has said it needs to scrap the allowance not only to balance the books but also to make the welfare system fairer and less complicated.
EMA, it argues, is expensive and "poorly targeted".
A mayor of London spokeswoman said Mr Johnson had no control over the education budget.