A group of almost 60 social policy experts has criticised as "fundamentally misguided" a government campaign telling people not to give money to beggars.
The open letter to the prime minister expresses alarm over what could be a "potentially harmful campaign" that, it warns, it could force people into crime and prostitution.
Suzanne Fitzpatrick of the University of Glasgow had the idea for the letter after the government announced an advertising campaign telling the public not to give money to beggars. Instead it urged them to donate cash to charities, help out in soup kitchens or give food and clothes.
The academics told Tony Blair that the immediate survival needs of beggars should not be ignored: "While it is unpleasant for the public to encounter people begging, it is a far more distressing and hazardous experience for the people who beg."
The letter says that efforts to force the homeless into hostels "disempowers one of the most vulnerable groups in society and infringes their basic human rights".
It warns that tougher policing of begging will compound social exclusion and says that giving to charities instead of to beggars is "ineffective and punitive".
The letter was signed by Dr Fitzpatrick and Catherine Kennedy (Glasgow University), Ruth Lister (Loughborough), Hartley Dean (Luton) and 53 other leading social policy academics.