Media playback is unsupported on your device Media caption Newsnight reporter Chris Cook's look at the FOI Act

Some of the most important government departments are not fulfilling their obligations under the Freedom of Information (FOI) Act, a Newsnight investigation has shown.

Ten years on from the Act's introduction, Whitehall is still resisting the transparency law.

For Newsnight I conducted a "mystery shopper" exercise, asking for the same, simple information from almost every central government department, posing as an ordinary member of the public.

The programme's FOI request asked: "For each foreign trip made by a minister in your department on official business in the past year, please could you tell me the minister's identity, destination, purpose of visit, the number of civil servants and the number of special advisers based in your department who were present for each trip."

Only two of the 13 government departments that were approached answered the question in line with the law. The Act gives people a right to get information from public authorities, so long as the data is easy to find and won't cause any harm.

Working with a senior civil servant, I worded the request in a way that was designed to be as simple to answer as possible - and not fall foul of the restrictions in the Act.

The intention was to see how different officials approached the same request - as well as get the information.

I was imagining the results would allow me to compare how fast departments were working.

But in the event, the Department for Education and the Department for Transport were the only two ministries to reply in accordance with the law.

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That outcome was concerning.

Given that departments make open data releases on this topic, and are supposed to routinely collate and publish information on the cost and staffing of trips, I was actually really only asking for two new pieces of information: the number of special advisers and the number of civil servants who were present on each trip.

I did expect departments to say that some of the information was online, but still provide the remainder.

I also anticipated that departments might find a reason to use one of the security or data protection exemptions to refuse parts of the request.

But they did not.

Six wrong replies

What actually happened was I received six replies dismissing the request, saying - wrongly - that all of the data was already available.

Those came from from the Ministry of Defence, Scotland Office, Wales Office, Cabinet Office, Department of Health and Department for Work and Pensions.

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By contrast, the Department for International Development, the Department for the Environment, Farming and Rural Affairs and the Department for Communities and Local Government all said they did not hold the information at all.

Both the Department for Business, Innovation and Skills and HM Treasury said that it would take a civil servant the equivalent of at least 24 hours solid work to get the data.

When 11 departments were presented with the same question, nearly half refused to answer the question because the information was already so easy to find. The others refused because it was so hard to get.

Officials might argue there are appeals processes, which could have resolved this.

Bureaucratic reply

But the Act anticipates that people should receive answers in 20 days, not after months of wrangling. The appeals are supposed to be the exception, not the norm.

I do not think any of the initial refusals we received were reasonable, except for the two full replies.

Still pretending to be a member of the public, I went back to departments after the initial reply, and one - the Ministry of Defence - replied very quickly with a correction.

Staff there genuinely seem to have just misread my request. But others did not.

I was completely ignored by some and the Cabinet Office sent an unhelpful and bureaucratic reply.

The big picture here is that the way the Act operates is capricious for users, and officials look to brush off requests.

Watch Chris Cook's report about his FOI request bonanza on Newsnight on Thursday 29 January at 1030pm on BBC Two.