The information requested falls within the responsibility of the UK Statistics Authority. I have asked the authority to reply.
As Director General for the Office for National Statistics (ONS), I have been asked to respond to your Parliamentary Question asking for the estimated number of qualifying Commonwealth citizens resident in the United Kingdom who are entitled to register to vote in all United Kingdom referendums and elections (HL 14208)
ONS does not maintain statistics of the number of people entitled to vote. However, the most recent estimate of the number of Commonwealth nationals aged 18 and over residing in the UK is 1,157,000 with a corresponding margin of error of +/- 46,000. This estimate excludes UK nationals.
The margin of error refers to the 95 per cent confidence interval and is a measure of the uncertainty associated with making inferences from a sample.
The figure provided is the closest approximation available for the number of qualifying Commonwealth citizens resident in the UK who are entitled to register to vote in UK elections and referendums. It is based on the Annual Population Survey (APS) and relates to the 12 month period from April 2010 to March 2011.
The estimate may not be exactly the same as the requested figures. The APS is a household survey which excludes most communal establishments and therefore some qualifying Commonwealth citizens may not be included. However, the estimate provided may include some Commonwealth citizens who are not eligible to register to vote. This is due to the following reasons:
there may be some Commonwealth citizens who require but have not been granted leave to remain in the UK;in Northern Ireland all persons must be resident for three months before they are eligible to register to vote. The estimate of Commonwealth nationals resident in the UK includes all persons regardless of duration of residence; and some Commonwealth citizens resident in the UK may be subject to a legal incapacity to vote (for example, detained convicted prisoners and offenders detained in mental hospitals).
Estimates provided in this response include Malta and Cyprus citizens. Although now EU member states, citizens of these countries are eligible to be registered to vote in respect of all elections in the UK. Further information on qualifying Commonwealth citizens can be found on the Electoral Commission website: http://www.electoralcommission.org.uk/qlossary/g.