If you are in full time employment, your income is 3x your rent, and pass your credit check + references you do not need to provide a guarantor.

You will be asked to provide a UK homeowner as a guarantor if:
Your annual earnings are less than 3 times your share of the rent.
You have not been in continuous full time employment for the last 12 months.
You are on a temporary employment contract/in a probationary period or have zero hours contract.
You are unable to provide a satisfactory credit check and/or rental reference.