Gordon Brown has said he wants the parliamentary standards bill – the "emergency' anti-sleaze legislation creating a regulator to take charge of MPs' pay and expenses – to be law before the Commons rises for the summer recess in two weeks. Now there seems to be at least a possibility that the House of Lords might stop him getting his way.

The Lords constitution committee has just published a report strongly criticising the government for trying to rush the bill onto the statute book. The three main parties are all committed to getting the bill passed before the summer holiday starts, and so, in theory, the fact that the 12-strong committee is opposed to that timetable should not make any difference. One source told me it would be "surprising" if the Lords as a whole tried to hold up the bill, given that it's about the House of Commons and that MPs want it passed quickly. But peers can be quite independent-minded and they may find the constitution committee's arguments persuasive. We'll know more when the Lords debates it for the first time on Wednesday.

This is the key section from the committee's report:

We are wholly unpersuaded by the government's case for this bill to be fast-tracked. There is an undoubted need to restore public confidence in the parliamentary system. It is not, however, clear to us that a cobbled together bill rushed through parliament will help rebuild public trust; on the contrary, if parliament cannot be seen to be scrutinising proposals with the thoroughness they deserve, public confidence in parliamentarians is likely to be further undermined. Governments should find the strength to resist falling into a temptation simply to see something done, which is no substitute for properly prepared policy and legislation.

Members of the committee were not impressed by the government's claims that the bill needed to be fast-tracked because there was "an urgent public demand" to sort out the expenses issue. "It appears that the key driver for the bill is public perception, rather than any specific policy outcome," the committee said. It also argued that a fast-track timetable was inappropriate for a bill with such important constitutional implications.

Self-regulation has been a central characteristic of both Houses of the United Kingdom parliament. The "exclusive cognisance" of each house to regulate its own affairs, free from intervention by the courts, has been a key feature of our constitutional framework. The bill breaks with that convention. This is a profound change which has the potential to give rise to conflict between parliament and the courts, the implications of which require very careful examination.

The report also includes a dig at the "constitutionally unorthodox" way the prime minister announced his plans to reform the system of MPs' expenses via an announcement on YouTube.

The bill has already been criticised in a memo from Malcolm Jack, the clerk of the Commons, in a report from the Commons justice committee and in a report from the joint committee on human rights. When the bill was being debated in the Commons, the government suffered one defeat and had to announce two further concessions. After Wednesday's second reading, the Lords will debate it again on Tuesday next week (the committee stage) and on Monday 20 July (report stage and third reading). Even if peers do not try to delay the bill, further concessions seem inevitable.