A postal vote mix-up has led to Haringey residents being sent incorrect instructions that could lead them to cast the wrong vote.

The council has admitted that postal voting forms have been sent out with a set of instructions saying voters should select just one candidate.

But, unlike in General Elections, voters can select up to three candidates in the council election on May 3.

In a statement, the council said: “We are committed to ensuring that not one single voter loses a single vote. We are therefore writing urgently to each affected voter to explain the error and give them the correct instructions.

“We are also taking steps to ensure that no further incorrect instructions are issued.”

The mix-up only relates to postal voters who received their packs on Saturday, April 14 – around 900 packs out of more than 22,000 applications.

It happened because printers accidentally used instructions written for local authorities with only one seat in each ward, instead of the three per ward in Haringey.

The remaining packs will be sent out with the correct instructions.

Haringey Liberal Democrat leader Gail Engert said: “Our democracy is too important for the council to allow mistakes like this.

“As well as the obvious problem that it will cost lots to redo the ballots, I also fear that we will see voters confused and casting incorrect votes. To avoid this danger, it is imperative that voters are given the clearest possible instructions when they get their new ballots.

“We also need to find out why this happened, so we can prevent a repeat. That is especially true as something similar happened in the local election before last. For that reason, I’m calling for a scrutiny inquiry into this incident in the new council year.”

People who have already returned their ballot and believe they have voted in error should contact the council’s Electoral Services team on 020 8489 1000.

The council will cancel the ballot and issue a replacement ballot paper.