As soon as you plead guilty to the charge you will have a criminal conviction. When you apply for British citizenship you must declare this criminal conviction. Only road traffic offences dealt with by way of a fixed penalty notice (parking and speeding offences) and offences which are "spent" under the Rehabilitation of Offenders Act 1974 do not have to be declared. It would be a criminal offence for you not to declare the conviction and you could be prosecuted.
It is not possible to state precisely how the conviction will affect your application for British citizenship. Home Office policy states as follows "We will normally disregard a single conviction for a minor offence resulting in a bind over, conditional discharge or relatively small fine or compensation order, if a person is suitable for citizenship in all other respects. By "minor offences" we mean speeding or other "regulatory" offences. Offences involving dishonesty (e.g. theft), violence or sexual offences are not classed as minor offences. Drink-driving offences, driving while uninsured or disqualified are not minor offences either." This is a quote from the following document:
Therefore, if the Home Office treats your conviction for using a mobile phone while driving as akin to speeding you should still be granted citizenship. However, if they consider that it is closer to drink-driving or driving while uninsured then they will refuse to grant you citizenship.
The sentence imposed by the court will be an important factor that the Home Office will consider when deciding whether the offence should be treated as a minor offence or not. I would also advise that when you make your application you should include some carefully drafted written representations as to why the offence should be treated as a minor offence akin to speeding in terms of seriousness. You should consider seeking the assistance of a solicitor or specialist immigration barrister to help you with your application.
I hope this answers your question. Please kindly click the green ACCEPT button so that I may be compensated for my time. Thank-you.
DISCLAIMER: Answers from Experts on JustAnswer are not substitutes for the advice of an attorney. JustAnswer is a public forum and questions and responses are not private or confidential or protected by the attorney-client privilege. The Expert above is not your attorney, and the response above is not legal advice. You should not read this response to propose specific action or address specific circumstances, but only to give you a sense of general principles of law that might affect the situation you describe. Application of these general principles to particular circumstances must be done by a lawyer who has spoken with you in confidence, learned all relevant information, and explored various options. Before acting on these general principles, you should hire a lawyer licensed to practice law in the jurisdiction to which your question pertains.
The responses above are from individual Experts, not JustAnswer. The site and services are provided “as is”. To view the verified credential of an Expert, click on the “Verified” symbol in the Expert’s profile. This site is not for emergency questions which should be directed immediately by telephone or in-person to qualified professionals. Please carefully read the Terms of Service (last updated February 8, 2012).