Are you now or have you ever been?

I was rejected last week as a Labour Party supporter. I’m in good company, along with comedians Jeremy Hardy and Mark Steel, but I was taken aback. When I rang the party headquarters to ask the reason, they told me: ‘We have evidence from Twitter that you are a supporter of Plaid Cymru.’

That threw me. I had signed up, full of hope. I wanted to vote for Jeremy Corbyn as leader and help turn the Labour Party back into a force for change. I am a former party member and used to live in Corbyn’s constituency, where I saw at first hand his commitment to a fairer world.

They took my £3 and sent me umpteen election communications but then, last Thursday (20 August), came the standard rejection email, with the words: ‘We have reason to believe that you do not support the aims and values of the Labour Party or you are a supporter of an organisation opposed to the Labour Party.’

When I signed up, I was asked to confirm that I shared these ‘aims and values’ and was not a member of an organisation opposed to Labour. The aims and values were not given, though, and the only place where I could find a full list was the Pendle consituency website. The document includes words and phrases I find inspiring, such as ‘democratic socialist’, ‘common endeavour’, ‘solidarity’, and ‘respect’; and the concept of redistribution of power, wealth and opportunity.

In contrast, the Labour Party’s national website does not list the aims and gives the values as: ‘social justice; strong community and strong values; reward for hard work; decency; rights matched by responsibilities.’ Conveniently, most of the key words and phrases have been lost or diluted in the bowdlerisation.

Which version do they want supporters to agree with? How am I to know if I agree with the value of strong values, without knowing what those strong values are? And what is meant by ‘decency’? The dictionary definition is ‘conformity to the prevailing standards of what is right’. Probably not socialism, then.

I ticked my agreement. Because although some of the new stuff did sound like the Conservatives, I like solidarity and respect.

But what is now in question is my support. The party with which I was aligned for most of my life, with which I hoped to realign, has been monitoring me on social media to gather ‘evidence’ against me without my knowledge or permission – and is not afraid to say so. It deems a liking for Plaid to be at odds with support for Labour, where I see two parallel progressive parties, each bobbing further left or right, depending on the times.

I was angry and confused. I examined my underused Twitter account for the ‘evidence’. I follow Leanne Wood, my Plaid MEP and my dear friend Mike Parker, who was a promising Plaid candidate in the general election in Ceredigion, where Labour stood no chance. I had also retweeted something over a year ago from Plaid Pride: ‘Congratulations @JillEvansMEP! Wales’ strongest voice on LGBT votes in Europe has been re-elected!’

I scroll down two years and see I retweeted Mike’s original announcement that he was running for office. I call out to my partner, Jane: ‘This could be what disqualified me!’ She replies: ‘It doesn’t matter. Stop trying to get inside their minds. They had no right to snoop on you, it’s intrusive and ridiculous.’

As Tim Turner has explained on his law blog, it was also probably illegal. You can’t vet people without telling them first and no one told us we were being vetted. The party invited the public to sign up and are now acting as if we are infiltrators.

Am I an infiltrator? In this year’s general election, after a lifetime of voting Labour in Manchester and London, I marked my cross for Plaid Cymru. I have lived for the past few years in Dwyfor Meirionnydd, a pretty safe Plaid seat where the Conservatives came in second and Labour only took 13.5% of the vote. I voted Plaid because they stand up for Wales and outlined clear anti-austerity policies; a vote for Labour would be wasted; and I wanted to be absolutely sure of ruling out a Conservative or UKIP win.

Even if they could get inside my head and know all this, does any of it define me as ‘a supporter of an organisation opposed to the Labour Party’? And how can they use that criterion at all, when I was only asked to tick that I was not a member of such an organisation? When I tell friends about the Twitter vetting, they think I’m joking, then compare it to being spied on by the Stasi.

Let’s not forget that Labour had issued an open invitation to new supporters – interim leader Harriet Harman announced in May that anyone on the electoral register could become a supporter and have a vote. Apparently the rules have changed.

My local Labour Party branch is now trying to help but even if I am reinstated (which looks unlikely), the whole episode has driven home one piece of crucial knowledge that I had buried during my short fit of optimism: party politics is corrupt, divisive and authoritarian, and even nice people can’t fix it.