Statutory Sick Pay
If you’re unable to work due to illness or are self-isolating due to Corona virus, and your employer doesn’t offer contractual sick pay, you can claim Statutory Sick Pay (SSP) if you usually earn at least £118 per week before tax. For the next 3 months at least, you can claim SSP from the first day of not working. Your employer pays SSP and you should tell them immediately, and at least within 7 days, that you need to claim it. You normally have to provide a GP fit note after 7 consecutive days of illness but at present you only need to provide a note from NHS 111 online:
https://111.nhs.uk/ 

If you qualify for SSP, you also qualify for some Universal Credit monthly payments towards rent costs and for Council Tax Reduction. Use the benefit calculator at the Turn2Us website to calculate how much you qualify for and how to apply for it:
https://benefits-calculator.turn2us.org.uk/AboutYou

SSP is paid for up to 28 weeks, at which point you’ll need to make an online Universal Credit claim on the grounds of long-term illness or disability:
https://www.gov.uk/statutory-sick-pay

Universal Credit
If you’re unable to work due to illness, are self-isolating due to Corona virus and do not qualify for Statutory Sick Pay (SSP), for example, if you’re not classed as an ‘employee’ due to being self-employed, are on a zero-hours contract that doesn’t offer sick pay, or usually earn less than £118 per week before tax, you need to make an online claim for Universal Credit. The monthly Universal Credit award will also include payments towards rent, children living with you, and includes an exemption from work searching and possibly additional payments if you’re assessed as unable to work due to illness or disability:
https://www.gov.uk/universal-credit 

If you live with a partner, you’ll need to make a joint claim and their income will be taken into account. Use the benefit calculator at the Turn2Us website to calculate how much you qualify for and how to apply for it:
https://benefits-calculator.turn2us.org.uk/AboutYou

Normally, once you’ve made an online claim for Universal Credit, you’re expected to call them to arrange a claimant commitment interview at the Jobcentre, in which you’re expected to agree with your work coach on the efforts you’ll make to find work. However, these have been cancelled for at least 3 months and might be conducted online, over the phone or, as is the case in some Jobcentres, it’s awarded on trust. You should be given instructions when you call the number given after submitting your online claim or on your online journal when it’s activated.

Normally, if you’re claiming Universal Credit on grounds of an illness or long-term disability that prevents you from working, you’re expected to provide a GP fit note and attend a Work Capability Assessment after 13 weeks of the claim. However, all face-to-face assessments have been cancelled for at least 3 months and instead it could be decided on paperwork such as medical evidence, online or over the phone. You should be given instructions when you call the number given after submitting your online claim or on your online journal when it’s activated.

Once you’ve been awarded Universal Credit, you’ll have to wait 5 weeks for payment and therefore can apply for an Advance Payment in the form of a loan of up to 100% of your estimated award, which is then repayable as a deduction from your award over 12 months. To apply for an Advance Payment, you normally need to go into the Jobcentre to provide ID but for the next 3 months at least you can apply on your online journal for this or by calling the helpline on 0800 328 5644.
If you have grounds for backdating your claim, you can apply on your online journal for a backdate of up to a month by sending a message to your work coach, do this as soon as possible after your online journal has been activated.

Jobcentres are obliged to support claimants who are vulnerable, homeless or lack a phone and/or internet access by arranging face-to-face meetings but this is often not the case - if they refuse to do this a complaint should be made, ideally with the support of a benefits advisor. Alternatively, claimants who lack internet access or the skills to make an online Universal Credit claim can call the Citizen’s Advice Bureau Help to Claim line for support on 0800 144 8444 in England, 0800 024 1220 in Wales and 0800 023 2581 in Scotland:
https://www.citizensadvice.org.uk/benefits/universal-credit/claiming/hel...

If you don’t have a mobile phone but do have internet access, enter eleven zeros in the online claim form and you’ll get notifications via email.

An up-to-date page on Corona virus and Universal credit:
https://www.understandinguniversalcredit.gov.uk/coronavirus/

New Style Jobseeker’s Allowance
If you need to make a Universal Credit claim because you’ve lost your job, and have paid enough National Insurance contributions over the previous 2 years, you can apply for New Style Jobseeker’s Allowance (JSA). You’ll still need to apply for Universal Credit for help with rent and children living with you but New Style JSA will be deducted from your monthly Universal Credit award. The advantage of this is that on New Style JSA you’re allowed to exceed the capital limit of £16,000 and your partner’s earnings aren’t taken into account: https://www.gov.uk/guidance/new-style-jobseekers-allowance

New Style Employment & Support Allowance
If you need to make a Universal Credit claim because you can’t work due to illness or disability, and have paid enough National Insurance contributions over the previous 2 years, you can apply for New Style Employment & Allowance (ESA). You’ll still need to apply for Universal Credit for help with rent and children living with you but New Style ESA will be deducted from your monthly Universal Credit award. The advantage of this is that on New Style ESA you’re allowed to exceed the capital limit of £16,000 and your partner’s earnings aren’t taken into account: https://www.gov.uk/guidance/new-style-employment-and-support-allowance