Parliament and the FOI exemption bill

It seems that the Labour Parliamentary Committee is supporting the Private Member’s Bill brought by Conservative MP David MacLean.

According to the Independent: 

The email from Labour MPs Tony Lloyd, Angela Eagle, Kevan Jones, Ann
Cryer, Joan Ruddock, Martin Salter and Don Touhig says: "We feel
strongly that the measures contained in the Bill, which would protect
the confidentiality of MPs’ correspondence on behalf of constituents,
are worthy of support."

However the BBC’s FOI expert Martin Rosenbaum has already said his view which is that

letters about the personal circumstances of constituents are already protected from disclosure under the Data Protection Act

Cabinet supporters for the Bill are said to be Jack Straw and Tessa Jowell, but the silence on the matter from most high profile politicians is deafening.