Engineers constructing a major new power line have reached a milestone with half of the controversial project now complete.

A total of 267 pylons on the 137-mile Beauly to Denny line have now been erected, according to the company carrying out the bulk of the work.

The line, which will carry renewable energy generated in the Highlands to central Scotland, was given the go-ahead by Scottish Government ministers in January 2010.

This was despite strong objections from countryside campaigners who said the project will destroy some of Scotland's most scenic areas and damage tourism.

Construction of the bulk of the power line is being carried out by SSE, with Scottish Power building a 12-mile stretch from Denny northwards, taking in most of Stirlingshire.

Engineers are said to have been working flat-out to complete as many pylons as possible before the start of winter, with the 700-strong team on track to complete the SSE part of the line by 2015.

An average of five towers are erected every week, the power company said.

Electricity was transmitted along part of the new line for the first time in July, and David Gardner, SSE's director of transmission, said news that the half-way point has been reached shows the progress being made.

"Following energisation of the north section of the line in July, this landmark is a further demonstration of the good progress being made, a testament to the teams of engineers who are working in some of Scotland's toughest terrain," he said.

The new line is part of SSE's £1.4 billion investment programme, he said.

"This investment is essential in allowing the connection of renewable energy and helping keep the lights on across the north of Scotland."

Mr Gardner also stressed the project's "positive contribution" in creating jobs and to both the local and national economy, saying that this could "not be underestimated".

Niall Stewart, chief executive of Scottish Renewables, said the new power line is "key to delivering Scotland's renewable electricity targets and essential to connect wind, wave and tidal projects in the north of the country to the grid".

He said: "Quite simply, there can be no wave or tidal industry in Scotland without it, so it is great to see SSE's section on track to be finished in 2015, by when Scotland will be generating more than half of its electricity needs through renewables.

"This is good news for the whole renewable energy industry and all those who depend on the continued growth of the sector.

"Investment in renewables topped £1.5 billion last year, and the jobs of more than 11,000 people in Scotland now depend directly on renewable energy development."