This question is academic.
Even if the entire population, including all of the Members of the House of Commons and the Lords, wanted it, Capital Punishment cannot be restored in this country whilst it remains a member of the EU and is a signatory to the European Convention on Human Rights (ECHR).
Conditions of membership of the EU and clauses in the ECHR prevent it.
A more relevent question would be "are you in favour of matters such as these (and lesser matters such as how many hours you are allowed to work, whether you can carry out DIY electical installations and window installations in your own home, who is allowed to enter and remain in this country, how much fish can be landed after being caught in international waters, etc. etc.) being determined by elected members of the British Parliament, or are you happy to allow such things to be decided by foreigners?"