But what about the performance of the Conservatives?

Spain's centre-left government, meanwhile, is taking a very different road. Its Social Democrat prime minister, Pedro Sanchez, loves pointing out the Spanish economy was the fastest growing amongst rich nations last year.Its 3.2% GDP growth was higher than America's, three times the UK's and four times the EU average.

Sanchez wants to legalise nearly a million migrants, already working in Spain but currently without legal papers. That extra tax revenue plus the much-needed extra workers to plug gaps in the labour market will maintain economic growth and ensure future pension payments are covered, he says.Spain has one of the lowest birth rates in the EU. Spanish society is getting old, fast."Almost half of our towns are at risk of depopulation," he said in autumn 2024. "We have elderly people who need a caregiver, companies looking for programmers, technicians and bricklayers... The key to migration is in managing it well."

Critics accuse Sanchez of encouraging illegal migration to Spain, and question the country's record of integrating migrants. Opinion polls show that Sanchez is taking a gamble: 57% of Spaniards say there are already too many migrants in the country, according to public pollster 40dB.In less than 30 years, the number of foreign-born inhabitants in Spain has jumped almost nine fold from 1.6% to 14% of the population. But so far, migration concerns haven't translated into widespread support for the immigration sceptic nationalist Vox party.

The Sanchez government is setting up what Ms Pace calls a "national dialogue", involving NGOs and private business. The aim is to balance plugging labour market gaps with avoiding strains on public services, by using extra tax revenue from new migrant workers, to build housing and extra classrooms, for example.

Right now the plan is aspirational. It's too early to judge, if successful, or not.By comparison around one in 50 were dropped across England and Wales.

The Met said the number included situations where police could not find an expert witness or were not able to obtain a required medical statement and to suggest it was simply down to lost evidence was misleading.It acknowledged that on "a rare number of occasions" evidence is misplaced, adding: "We continue to make improvements to our recording systems to minimise this risk."

The NPCC said: "When evidential issues occur in a case, the CPS will raise this with police for any action deemed necessary and we will work together to ensure these are resolved wherever possible."The results of a consultation by the Law Commission, which proposed re-establishing a national forensic service and making the mishandling of evidence a criminal offence in some circumstances, are set to go before Parliament next week.