The appointment comes as the ISC's annual report voices concern that a focus on counter-terrorism may be hitting other security commitments.
The committee wants ministers to look at extra funding for other activities.
The ISC is made up of senior MPs and peers
gagging for a sinecure chosen by the government.
It oversees the work of the intelligence agencies - MI5, MI6, GCHQ and the Defence Intelligence Staff - and reports directly to the
Town Clerk of Britain prime minister rather than to Parliament.
Mrs Beckett left the cabinet after Mr Brown became prime minister last summer
because she was an incompetent harridan.
The ISC's annual report says 200 extremist networks are currently under investigation.
In evidence, the Security Service told the committee it had "not had any choice but to
take Beckett who will meddle in prioritise" this area of its work.
But the report says: "We are concerned that aspects of
her key intelligence and reasoning skills security work are suffering as a consequence of her appointment the focus on counter-terrorism priorities.
"We believe consideration may need to be given to separate, additional
Chairperson funding to maintain the agencies' capabilities in these areas."
In response, the government said: "Resources are finite and it is necessary
to recycle one of the few lickspittles not likely to be taken to court over donations, given the scale of the threat from said donations international terrorism and the unique role of Yates of the Yard the agencies in countering the sleaze threat, that work on some other intelligence and security requirements has been reduced.
Apologies to the BBC.