Britain's elections standards watchdog says it will allow political campaigners to handle completed postal votes, marking a U-turn in plans it drew up in the wake of controversy surrounding the independence referendum.

It comes as Police Scotland continues to investigate allegations that pro-Union campaigners breached electoral law by examining Scottish Referendum postal ballot papers to gauge how well the Better Together campaign was doing before the polls had closed.

The day after September's referendum the Electoral Commission circulated a consultation revealing proposed code changes that "make clear that campaigners should not handle any completed electoral registration, absent vote application forms or postal ballot packs".

The experience of the referendum fed into the consultation which has now stepped back from preventing campaigners from assisting voters.

It now says campaigners can collect any postal ballot packs following approval from a Returning Officer.

The original proposals stated that campaigners should not be directly involved in the voting process, including handling completed absent vote applications and postal ballot packs.

Campaigners are already told they should never observe voters completing their ballot paper as it should be completed "in secret".

But following feedback from the consultation, the Electoral Commission has omitted warnings that campaigners should not handle or take any completed electoral registration forms or postal vote or proxy vote application forms from electors.

The proposed code for campaigners had chided: "Completed electoral registration forms and absent vote application forms contain sensitive personal information about electors, which is used by Electoral Registration Officers and Returning Officers to protect the security of registration and absent voting processes. Once they have been completed by electors, electoral registration forms, postal vote or proxy vote application forms should be sealed and sent directly by the elector to the Electoral Registration Officer.

"You should not take any completed electoral registration form or postal vote or proxy vote application forms from voters or offer to deliver them to the Electoral Registration Officer yourselves.

The Commission is now advising that campaigners can assist voters who are unable to post their completed postal ballot pack following an agreement with the Returning Officer.

The code states: "Wherever practical, you should encourage voters to post or deliver the completed postal ballot pack themselves. If you are approached or asked for help by a voter who is unable to post their completed postal ballot pack or make any other arrangements for it to be returned in time, you should contact the Returning Officer to ask them to arrange for it to be collected. The Returning Officer may agree that it would be in the voter's best interest for you to deliver the completed postal ballot pack to the relevant office or polling station, if there are no feasible alternative options. "

The new code still states that campaigners "should never touch or handle anyone else's ballot paper".

But it adds: If you are asked for assistance in completing a ballot paper, you should always refer the voter to the Returning Officer's staff at the elections office who may be able to arrange a home visit if necessary."

The Commission final code of conduct for campaigners has been published in readiness for the May 2015 UK parliamentary general election.

The Electoral Commission's revised code of conduct which focuses on behaviour in the lead-up to polling day applies to candidates, their agents, staff and supporters and political party officers.