tories urge  change at the top  tory delegates are gathering for what is expected to be their last conference before the general election  declaring britain needs  a change at the top .  the party goes into its spring forum trying to highlight what it sees as a clear choice between it and labour. tory co-chairman liam fox has opened proceedings with a speech criticising tony blair s record in government. labour s rule has been characterised by  lost trust and failure to deliver   he told the brighton conference. he also attacked the government s  failure  to control immigration and asylum and criticised its record on the nhs  telling delegates labour cannot be trusted on education or crime. a tory government would sort out the  shambles  of immigration  put patients before statistics and bring discipline to schools  he said. dr fox also underlined tory promises to cut tax by £4bn.  bbc political correspondent shaun ley says opinion polls suggest the tories still lag some way behind labour on the issues of health  education and the economy. conservative leader michael howard  who had been due to welcome delegates to the conference on friday  will address them in a lunchtime speech. his welcome address had to be postponed after he stayed in london to lead the party s opposition to the prevention of terrorism bill in its lengthy progress through parliament. the bill was finally passed on friday evening  after more than 30 hours of debate. mr howard is likely to defend his party s handling of the bill  which was only passed after the conservatives accepted prime minister tony blair s promise that mps would be able to review it within a year.