This newspaper supported London's Olympic bid, and we still believe that the Games will be a wonderful celebration of the human body and spirit. We cannot wait for the carnival to begin. But some of its organisers make it hard to suppress the British tendency to grumble about the incompetence of those in authority.

Every time we are tempted to say that glitches are to be expected and that some disruption of London life is a price worth paying, it seems that the organisers are ever more determined to make the BBC's spoof Twenty Twelve look like a promotional documentary.

The failure of the Government to ensure the provision of adequate numbers of well-trained security staff is inexcusable. Today we report that the Home Office was warned 10 months ago that G4S might not be able to supply the contracted staff, contrary to the impression given by the Home Secretary on Thursday that she had just learned that there was a problem. She must now must answer 10 questions.

1. What did you know and when did you know it?

2. Were you aware of the report by HM Inspectorate of Constabulary, which raised concerns about the readiness of G4S in September 2011?

3. Why was effective action not taken until last week?

4. If, as you told the House of Commons last week, "We were receiving reassurances from G4S until very recently", and you say you had been "testing and challenging the assurances", why did you not realise that there was a problem until last week?

5. Precisely how "recently" did you cease to receive assurances from G4S?

6. When James Brokenshire, your junior minister, said, "We've obviously been monitoring the progress and been challenging them, asking the questions, really going down, kicking the tyres and doing all those sorts of things," what sort of things did he mean?

7. Why did the Organising Committee tell Keith Vaz, chairman of the Home Affairs select committee, that the problem "crystallised a fortnight ago, but there had been concerns for some time"?

8. Why did you then tell the Commons as late as Monday last week, "We have been testing our plans thoroughly and are confident that our partners… will deliver a safe and secure Games"?

9. If, as you told the Commons, you "had had discussions with the MoD about whether troops would be available for the contingency", does this not suggest that you realised that a shortfall in security staff was possible?

10. Did you mislead MPs on Thursday when you said, "The absolute gap in numbers was crystallised finally only yesterday"?

It seems likely that some senior staff in G4S knew that there was a problem long before the "eight or nine days ago" to which Nick Buckles, the chief executive, admitted yesterday. The Independent on Sunday has spoken to junior staff in the company who said that there was "no system in place... from the start". It is inexplicable that neither the Organising Committee nor the Home Office had ways of verifiably checking the company's progress. The main culprit is of course G4S, but someone in government, possibly Ms May herself, must also be held accountable.

We are still optimistic that the Games themselves will be a success, which will be enjoyed by millions around the world. But the security provision has been an unforgivable failure.