A new three-tier lockdown system is being planned for England, with leaked government documents paving the way for potential harsher restrictions including the closure of pubs and a ban on all social contact outside of household groups.

The draft traffic-light-style plan, seen by the Guardian, is designed to simplify the current patchwork of localised restrictions, which apply to about a quarter of the UK. It also reveals tougher measures that could be imposed by the government locally or nationally if Covid cases are not brought under control.

Called the “Covid-19 Proposed Social Distancing Framework” and dated 30 September, it has not yet been signed off by No 10 and measures could still be watered down.

Alert level 3 – the most serious – contains tougher measures than any seen so far in local lockdowns since the start of the pandemic. They include:

• Closure of hospitality and leisure businesses.

• No social contact outside your household in any setting.

• Restrictions on overnight stays away from home.

• No organised non-professional sports permitted or other communal hobby groups and activities, such as social clubs in community centres.

• Places of worship can remain open.

Schools are not mentioned in the draft. A government source said this was because Boris Johnson had made clear that classroom closures would be a last resort and the reopening of schools was considered within Whitehall to have been a relative success.

Any attempts to impose more stringent measures are expected to provoke renewed anger among Conservative backbenchers, who are likely to demand a vote in parliament should they come into force.

A government source said the measures in the draft document, particularly those under alert level 3, had not been finalised and the document still needed to be approved by ministers in the Covid-operations committee and by the prime minister.

Marked “official – sensitive”, it says the government’s Scientific Advisory Group for Emergencies (Sage) has advised that a package of measures, rather than single changes, will be most effective in controlling the spread of the virus.

“Preventing household mixing and closing businesses and venues in which there is close social interaction was recommended as the best way to reduce R,” it says, referring to the rate of infection that the government aims to keep below 1.

The three-tier system should improve compliance with the rules: “Research tells us that people would welcome a clearer and simpler structure to the advice and rules that they should follow,” it says, acknowledging that “many people do not have a clear understanding of the rules that apply to them”.

The document says that alert level 3 would be “triggered in geographical areas or nationally when alert level 2 measures have not contained the spread of the virus, or where there has been a significant rise in transmission”.

Under alert level 2, people must not meet others outside of their household in private dwellings or gardens, apart from their support bubble, or in pubs, restaurants or other settings. Level 2 will be “triggered in geographical areas or nationally when there has been a rise in transmission, which cannot be contained through local responses”.

Visiting care homes will only be allowed in exceptional circumstances and travel should be limited to essential purposes, though holidays are permitted within households.

People can continue to play organised team sports. Weddings are limited to 15 attendees and receptions would not be permitted, with funeral numbers also slashed from 30 to 15 attendees.

Alert level 1 contains restrictions currently in place across England, including the “rule of six” for gatherings indoor and out, the wearing of face-coverings, the 10pm curfew on hospitality businesses and numbers limited to 15 at weddings and 30 at funerals.

A Whitehall source said the levels were intended to be “minimum standards” and specific local circumstances would also be taken into account.

Downing Street declined to comment. A government source said it was an “early draft and proposals are still being considered by ministers”.

The shadow health secretary, Jon Ashworth, said Labour had long called for a simplification of the rules and said ministers must now make clear the criteria that would be applied to put areas into different alert levels.

“Vast swathes of the north of England and the Midlands are under a form of lockdown with a myriad of different rules applying,” Ashworth said. “In recent days, Boris Johnson got himself into an utter muddle over these rules, confirming that the ad hoc way in which decisions are made causes confusion.”

Johnson recently had to apologise for suggesting people could meet in pub gardens in north-east England after misinterpreting the rules – a mistake that a cabinet minister blamed on a “gotcha” question.

Ashworth said that the lockdowns meant “unanswered questions about the upcoming school half-term or Christmas” and said that families needed to know their area was being treated fairly and getting support.

“Keir Starmer has called for clear criteria to apply when an area goes into lockdown and how it escapes. Ministers are now admitting how confusing their approach has been,” he said.

A Department of Health spokesman said: “We are seeing coronavirus cases rise at a rapid rate across the country and, given how serious this virus is, it is vital everyone plays their part by following the rule of six, washing their hands, practising social distancing and wearing a mask in enclosed spaces.

“As we have shown, we are prepared to take action decisively when it is necessary, and it is of course right to look how we make sure everyone understands and complies with the restrictions that will keep us all safe.”