The Government department responsible for supporting the Prime Minister and Deputy Prime Minister is to be kept under watch after a high number of complaints were made to the data watchdog about the timeliness of its responses to Freedom of Information (FoI) requests.
The Information Commissioner's Office (ICO) will monitor the Cabinet Office, the corporate headquarters for government, along with the Crown Prosecution Service (CPS), which is responsible for prosecuting criminal cases investigated by the police in England and Wales.
Along with Hackney Council in London, the Cabinet Office and CPS will see their FoI responses examined between January 1 and March 31 and failure to show signs of improvement could lead to enforcement action.
Under the Freedom of Information Act, a public authority must respond to an FoI request within 20 working days.
Information Commissioner Christopher Graham said: " Responding to FoI requests within the statutory time limit of 20 working days is basic to delivering transparent and open government.
"While extensions may sometimes be justifiable for particularly complex requests, these three authorities have been selected for monitoring after serious shortcomings were identified in the time each of them has been taking to respond to FoI requests.
"It is particularly disappointing to see that the Cabinet Office has failed to maintain the improvements recorded three years ago when the authority was also monitored over the timeliness of its FoI responses.
"On that occasion, the Cabinet Office signed an undertaking to raise their game. Their inclusion on the latest monitoring list should act as a warning to others that lessons learnt from monitoring have to be sustained."
After reviewing the results of the last monitoring period between July 1 and September 30 last year, the ICO said the Home Office is being monitored for an additional three-month period as, despite improving each month, it did not achieve satisfactory levels of performance in the timeliness of its FoI responses.
South Tyneside Council and Sussex Police improved their performance and are no longer being monitored.
Between April 1 and June 30 last year, the Metropolitan Police did not make satisfactory improvements to the timeliness of its FoI responses and the monitoring period was extended by a further three months. The ICO is currently considering the results from the extended period before deciding whether further action is required.
The London Borough of Barnet and Manchester City Council improved and are no longer being monitored.
A Cabinet Office spokesman said: " The Cabinet Office takes seriously its responsibilities under the FoI Act.
"We deal with many of the most complex and sensitive cases in government - including previous administrations - and we try to keep the Commissioner's office informed when these affect performance.
"There is only one quarter in 2013 where the Cabinet Office's performance was narrowly below the level the Commissioner has previously found acceptable.
"During this quarter we had a 23% increase in requests, most of which focused around the funeral of Margaret Thatcher, the Leveson Inquiry and information about Jimmy Savile.
"Even then we still answered more than eight out of 10 requests on time.
"We have made significant efforts to address the increased number of requests and the most recent data shows an improvement on that quarter. We will work with the Information Commissioner to provide him with the information needed during this monitoring period."