My latest surgery brought the debates over what legal measures are acceptable in the fight against terrorism right to my doorstep. For one of the people who came to see me was Mouloud Sihali. He was tried – and acquitted – in relation to the Wood Green ricin plot of 2003, but it is clear that the authorities still very much suspect him.

A bit of background first, as I’ve always been a bit uneasy about some events around the ricin plot. First, news of the incident was not promptly reported to key leaders in Haringey’s local emergency planning due to – a senior source told me – “news management by Number 10”. I can understand keeping information from the public for a short time to avoid undue panic etc, but to have Number 10 directly intervene to stop local emergency planning officials know smacks of something wrong – particularly as this was potentially an evacuation scenario.

Second, when news did become public it was all about a ricin plot being thwarted and the story basically was “ricin found, terrorists stopped, all now ok” – except that it then turned out there was no ricin. (And if the absence of ricin was the reason for not telling emergency planning officials initially, then how come its absence didn’t make it to the media? Was someone wanting the threat to sound worse to the public than it really was?).

Third, the Government has tried to use the ricin plot as justification for extending the period people can be detained without trial. It is true that one of the people skipped to Algeria – but he was actually released after only two days, so even under current laws, the police could have kept him in detention for much longer if they’d wanted to. And anyway he could have been charged with acts preparatory to terrorism. If this was a major terrorist whose existence would justify allowing people to be detained without trial for 90 days – why did the police let him go after just two?

All of which adds up to good grounds for being sceptical of how the ricin case has been handled, but that doesn’t mean everyone accused is all sweetness and light. Indeed, Mouloud Sihali himself was convicted of a passport offence. However, as quite a few people were caught up in it all, it doesn’t follow from the final conviction of Kamel Bourgass that everyone else charged at some point was necessarily involved in the plot.

Mr Sihali had come to see me (and was happy for me to talk publicly about his visit) because he is under a virtual control order. Without actually being under a control order – and despite being cleared of the ricin plot and freed (completely free) for five months – he is now tagged, under curfew, not allowed to have a mobile phone or use the internet, or to have visitors to his room, and he has to report each day to the police. Free for five months – again there’s this nagging doubt that enters my mind about quite what the authorities are really up to. If they are convinced he is a terrorist – well why was he let wander round completely free for five months? Is it that they’ve changed their minds back and forth as to whether he really is a terrorist – and if they’ve been changing their minds, how good then is the evidence?

He’s now facing deportation as a threat to the security of our country, but the evidence will be judged in secret and the evidence will never be seen by either the normal court system nor Mr Sihali.

And so this is the problem. As he’s been convicted of a passport offence and was in this country illegally, I don’t have a problem with deportation action being taken against him and being judged in an open, public process. But he’s facing deportation on the grounds of being a threat to national security – i.e. if deported this way he’ll have the stigma of being thought a terrorist hanging over him for the rest of his life. That is an awful burden to carry … unless he really is a terrorist. Yet he doesn’t get the chance to argue his own innocence – and his argument is that he should be given a chance to clear his name against the secret evidence. (You can read some of his case in his statement on this website).

So here sitting in front of me I had the whole problem in a nutshell around the issue and the legality of control orders and secret evidence, the terrorist threat and civil liberties. Getting it wrong either way brings huge consequences – letting a terrorist go free or tarring an innocent man for life.

He is one of my constituents – should I be fighting to help an innocent man, or would I be aiding a terrorist? I have no idea, without knowing what the secret evidence is. My only route is to try and get a meeting with Home Secretary John Reid to find out more about what evidence does exist, seek advice and find out what routes are actually open to Mr Sihali to pursue.

But whereas I trust our judicial system to be fair and just – my confidence in this Government’s dealings with truth and trust has been fundamentally eroded – especially when you add in the issues about how they have already behaved over the ricin plot to their abuse of the public trust with the exaggeration and manipulation of evidence over WMDs in Iraq.

And even if all the evidence stacks up, and the man is a terrorist – is deporting him really the answer? Does shuffling a terrorist to another country really help when the accusation is that he’s part of an international terrorist organisation and there is an international war on terror?

Underneath all the veneer of Labour’s tough talk on terrorism, here I am left facing a case where there’s a risk an innocent man in unjustly tarred as a terrorist without a chance to clear his name, but if he’s really a terrorist – then simply deporting him ain’t much of a punishment or deterrence either.