CTM90665 | Corporation tax self-assessment (CTSA): Claims and elections: Consequential claims and elections - deliberate or careless

FA98/SCH18/PARA65 (1) and (2) provide that when you make an assessment on a company where a loss of tax is involved as a result of deliberate or careless conduct it can make additional claims. It cannot make additional elections.

The only claims it can make are those that can be given effect in that assessment. They must therefore be made before you issue the assessment or in the appeal period.