The new service will initially follow the timetable of the current Saturday afternoon sailing; departing Stornoway at 1430hrs to arrive in Ullapool at 1730hrs then departing at 1815hrs arriving back in Stornoway at 2100 hrs.

CalMac had previously chosen not to operate on a Sunday out of respect for the religious beliefs of part of the local community. However a legal opinion which stated that the company's stance is more than likely to be in breach of the Equality Act 2006, has forced the company to review its position.

In addition, a steady rise in ferry traffic since the start of the year, following the introduction of the Road Equivalent Tariff pilot in October 2008, has led to complaints from islanders that they were increasingly experiencing difficulties securing space on Saturday and Monday sailings on the Stornoway/Ullapool route.

Peter Timms, Chairman of CalMac said: "Our consultation process sought to find a way of meeting our legal obligations and respecting local traditions, and we believe we can achieve that by operating one return trip a day, departing in the afternoon and returning late in the evening. This will minimise the impact on the culture and amenity of the islands, while at the same time providing economic and social benefits.

"We remain acutely aware of the sensitivities surrounding Sunday sailings, but we cannot operate unlawfully nor fail to provide lifeline services when there is a growing demonstrable demand from the communities we serve."

"During the consultation process, we received representations from Harris businesses and residents for a Sunday service between Harris and Uig in Skye, but we do not believe that is necessary at present and that the Stornoway-Ullapool service will be able to meet demand for all traffic to and from Lewis and Harris on a Sunday."

He added: "We would like to thank everyone who took part in the consultation process for their time and assure those opposed to Sunday sailings that despite media reports, this outcome was never 'inevitable' and we have listened very carefully to their concerns.

"We appreciate they will be disappointed but hope they will acknowledge the difficult situation in which we found ourselves and that by limiting the service to a single return trip, at times which minimise the potential for a clash with church services, we have done everything we can to respect their preferred way of life and minimise the impact of this new service on that."

Comhairle nan Eilean Siar have expressed deep disappointment at the CalMac decision.

The Comhairle also stressed their dismay at the lack of consultation and CalMac's refusal to make public the legal advice that the decision is based on. The Comhairle will now be seeking confirmation that the Scottish Government has approved the change.

Comhairle Leader Angus Campbell said: "This is not a matter of surprise but it is still a disappointment. I am particularly unhappy that Caledonian MacBrayne have refused to meaningfully consult with the wider Comhairle, nor have they provided us with the legal advice that they have based the decision upon."