Somewhere to hang your sword? It’s what every socially progressive, green politician needs. That was the offer made to the UK’s first Green MP, Caroline Lucas, when taking her place in the House of Commons, and this account of her Westminster years reads like the field journal of an incredulous anthropologist stumbling on an unusual tribe. You can’t, of course, even call colleagues by their real names during parliamentary business; instead, MPs have to work out if they are an honourable member, a right honourable one or an honourable friend. The latter gives the book its ironic title. It is the term reserved for members of your own party and, in the Commons, Lucas is a party of one.

What comes across as most odd is parliament’s lack of self-knowledge about its deep strangeness. There is an assumption that its peculiarities can be laughed off as quaint and traditional rather than dysfunctional and alienating. The withholding and giving of privileges – such as offices to work in – by party officials to compel compliance seems lifted straight from a prison playbook. This combines with an extraordinary sense of entitlement that surfaced in the recent cases of old‑hand MPs Malcolm Rifkind and Jack Straw. You could argue that the detachment from reality begins with the enforced habit of calling each other “honourable”, regardless of evidence to the contrary, and the practice of not being able to accuse another member of lying. But Lucas is relentlessly polite about her fellow MPs who, with few exceptions and judging from her own account, seem barely to deserve the courtesy. As she peels back layers of tradition like Westminster’s over-priced and ornate Pugin-friendly wallpaper, there seems little to honour.

Most remember the policy compromise that saw the Liberal Democrats unglue themselves from their promise on university tuition fees in order to build the coalition. But Lucas points out that it wasn’t long before the coalition’s shiny new commitments were also being broken. First dropped was a pledge to close a loophole that allowed illegal tropical timber to be traded within the UK, even though it couldn’t have entered the country legally. Lucas’s attempt to rectify the situation by introducing her own bill was talked out, bringing home the limitations of having too few honourable friends.

And, with an election looming, she remains alone, apart from some more clubbable Scottish Nationalists, members of Plaid Cymru and the sympathy of Commons officials. These overlooked public servants, Lucas points out, are particularly proud of the legacy of the suffragettes, and welcomed her as fresh air in an otherwise ossified institution. They probably played a hand in her winning one of the greatest Westminster power plays of all: getting a decent office.

Lucas exposes the political conjuring trick that punishes the victims of the economic crisis for the crimes and incompetence of its perpetrators. In pulling apart the statistical lies – sorry “dissembling” – of ministers such as Iain Duncan Smith to justify a punitive benefits regime, the point is made that austerity is an explicitly ideological, not rational or evidence-based, policy programme. This shouldn’t be a surprise. Private Eye’s Richard Brooks showed in his book The Great Tax Robbery that, pound for pound of criminal activity, HMRC were 1,800 times more likely to prosecute benefit fraud than tax fraud.

At HMRC, 300 people working in the gloriously titled Affluent Compliance Unit chase taxes dodged by the rich. At the Department for Work and Pensions 3,200 staff chase wrongly paid benefits, only some of which will result from deliberate fraud, worth just a fraction of the taxes lost from the rich. As this already overworked MP’s office fills with the human fallout of policies both cruel and deceptive, so the pages of Honourable Friends? fill with indignation. During the first two years of the coalition government, when cuts “were being voted through night after night, sales of champagne in the restaurants and bars of Westminster rose from £31,000 to £35,000 per year”.

Some tales grip then end abruptly, like the one about Lucas’s maiden speech, which used parliamentary privilege to name the litigious company Trafigura in a case that saw toxic waste dumped in Africa. And the book can be episodic, which is perhaps inevitable when you are your party’s parliamentary spokesperson on, well, everything.

But there is myth-busting here on everything from drugs to housing, wildlife to energy policy. If you have come across the Greens for the first time via the recent on-air gaffes of current leader Natalie Bennett or the mockery of some of their ideas, you might be surprised by the simplicity and pragmatism of their core policy: green public investment in housing and infrastructure to give people more comfortable homes and lower energy costs. They pledge to cut pollution, improve health, create jobs and lay the foundations of a modern, low-carbon economy. This would be paid for using fairer taxation and a variant of quantitative easing, already used to support the banks.

Compare that with the assumptions underpinning all the bigger parties’ policies, which suggest it is viable to grow the economy infinitely on a finite island, and the mainstream parties appear more exotic than the Greens do in their attempt to ground economics in the real “real world”.

You could read Lucas’s book as an effective summary of key debates on the UK’s future. But even more powerfully, it opens the door on a political past we are condemned to live with and sniffs the stale air of an institution to where we outsource our democracy. Stepping back, it is not Lucas who looks all alone in Westminster but Westminster that looks odd and out of place in the world. Far from hanging up swords, you suspect that, by the end of the book, many more readers will want to take up theirs to campaign for change.

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