It’s the people versus the peers, at least as far as some overly-excited Brexiteers are concerned. The bill to trigger Article 50 starts its passage through the House of Lords today, and with it, a row about the unelected chamber and how it ought to behave as far as Brexit is concerned.

This week will, largely, be sound and fury. More peers have signed up to speak than since Tony Blair got rid of the bulk of hereditary peers, triggering a 200-peer long queue of parliamentarians there to rage against the dying of the light, before, inevitably, the Commons prevailed over the Lords.

And to be frank, the same is ultimately going to happen with Article 50. From former SDPers, now either Labour peers or Liberal Democrat peers, who risked their careers over Europe, to the last of the impeccably pro-European Conservatives, to committed Labour and Liberal politicians, there are a number of pro-Europeans who will want to make their voices heard before bowing to the inevitable. Others, too, will want to have their “I told you so” on record should it all go belly-up.

The real battle starts next week, when the bill enters committee stage, and it is then that peers will hope to extract concessions from the government, either through defeat in the Lords or the threat of defeat in the Lords. Opposition peers will aim to secure concessions on the process of the talks, rather than to frustrate the exit.

But there are some areas where the government may be forced to give way. The Lords will seek to codify the government’s promise of a vote on the deal and to enshrine greater parliamentary scrutiny of the process, which is hard to argue against, and the government may concede that quarterly statements to the House on the process of Brexit are a price worth paying, and will, in any case, be a concession they end up making further down the line anyway.

But the big prize is the rights of EU citizens already resident here. The Lords has the advantage of having the overwhelming majority of the public – and the promises of every senior Leaver during the referendum campaign – behind them on that issue. When the unelected chamber faces down the elected, they like to have the weight of public opinion behind them so this is a well-chosen battleground.

But as Alex Barker explains in today’s FT, the rights of citizens aren’t as easy to guarantee as they look. Do pensions count? What about the children of EU citizens? What about access to social security and health? Rights that are easy to protect in the UK are more fraught in Spain, for instance. What about a British expat, working in, say, Italy, married to an Italian, who divorces, but wishes to remain in Italy afterwards? There is general agreement on all sides that the rights of Brits living in the rest of the EU and citizens of the EU27 living here need to be respected and guaranteed. But that even areas of broad agreement are the subject of fraught negotiation shows why those “I told you sos” may come in handy sooner than we think.