Alkali levels of the most common cements have never been limited by British Standards. But after the 'concrete cancer' scare of the 1980s, readymix and precast concrete producers began to demand consistent alkali levels from cement companies.
This information enabled them to design mixes with a very low risk of alkali silica reaction.
Before the advent of the new harmonised cement standards in 2001 all UK cement producers were covered by the BSI Kitemark scheme. As part of this scheme BSI assessors routinely checked that all tests on the cement from each works were being performed and reported correctly. This included tests for alkali content.
But in 2001 the European CE marking system became mandatory and virtually eliminated the Kitemark.
BSI continued to monitor cement works, but only for compliance with the new harmonised standard. As this set no limits on alkali content, the testing regime for alkalis fell outside the BSI's remit.
This would give the opportunity for rogue operatives to falsify alkali test certificates with comparative impunity.