A new public square is planned for the Royal Mile in the Scottish capital as part of a £150 million development in the Old Town World Heritage Site.

Developers said a major milestone in the New Waverley development, rebranded after the separate Caltongate project by a different company at the same site collapsed, is to be reached next month when work begins on the Royal Mile link.

New developer Artisan Real Estates Investors unveiled plans which include a 46-apartment Adagio Aparthotel which will face directly on to the Royal Mile, behind a retained facade of the C-listed Sailors Ark building.

The hotel will overlook the new £6.5 million public square, which is a focal point designed to "create a vibrant central hub" for New Waverley.

It also includes shops, restaurant and bar facilities on the ground floor of the hotel.

Construction work on the initial development phase of two Whitbread hotels with frontages on to East Market Street and Cranston Street is currently towered over by twin tower cranes on the site.

Work on the two hotels - a 127-room Premier Inn and a 121-room Hub by Premier Inn - began in November 2014 with a completion date set for mid-2016.

Clive Wilding, Artisan's Project Director, said: "The breakthrough to the Royal Mile marks a significant stage in the evolution of New Waverley, and its transformation of Edinburgh's Old Town and the entire city centre area.

"We are now seeing New Waverley's true scope and potential being delivered before us - a broad sweep of an historic part of the city integrating Edinburgh's busy New Street and Market Street with Waverley Station and the Royal Mile.

"The new public square, with stunning views over Calton Hill, will form a vibrant hub for this flagship mixed-use development and its surrounding area, creating an entirely new destination for Edinburgh."With it, we are creating the very heart of our development - a vibrant and pedestrian-friendly urban centre mixing open public spaces with high quality homes and offices, as well as restaurants, shops and hotels linking directly to one of the most iconic streets anywhere in the world."

He added: "We are working closely with the City of Edinburgh Council to create a community partnership to breathe new life into the area, using recently released funding.

"This includes arts projects such as the graffiti-based artworks on site hoardings and community events throughout the year."