Plans to automatically register voters cleared the penultimate hurdle in the Senedd’s legislative process – with 400,000 people potentially set to be added to the register.

Mick Antoniw, who is counsel general, the Welsh Government’s chief legal adviser, described the elections and elected bodies bill as groundbreaking.

He told the Senedd an incoming Labour UK Government would be committed to following Wales’ lead on automatic registration, with a similar model likely to be rolled out.

He said: “For Wales, It will mean potentially some 400,000 people being added to that register.

“If it is extended to the rest of the UK for non-devolved elections – you are talking about seven or eight million people who are not on the register.

“Now, it says something about our democracy when you have so many people who are not on the register – not even in a position to vote.”

Under the bill, Welsh ministers will be under a duty to improve diversity in Senedd and council structures – with tailored support for characteristics protected by equality law.

The bill, which has been overshadowed by contentious amendments about deception, would also lay the groundwork for councillors to be given cash when they are voted out.

Councillors who unsuccessfully stand for re-election could receive “resettlement payments”, dubbed in some quarters as “golden handshakes”, but those who stand down would not.

The policy aims to remove barriers, such as for people with caring responsibilities, and ease the transition for those who are giving up their careers to stand for election.

Adam Price tabled ultimately unsuccessful amendments, calling for voters to be given a “right to know” whether artificial intelligence has been used in electoral literature.

The former Plaid Cymru leader raised a “frightening” recent Dispatches documentary on the potential for technology to have a detrimental impact on democracy.

The bill now moves to the fourth and final legislative stage – a vote of the whole Senedd on the proposals as amended – which has been pencilled in for 9 July at about 4pm.

With Labour and Plaid Cymru’s support, and no legal challenge expected, the bill is likely to be passed.