Nortel appears to have laid off senior staff in the UK who were responsible for the company’s unified communications partnership with Microsoft.

Those leaving the company this week include John Mann, who led Nortel’s unified communications business in Europe, the Middle East and Africa (EMEA). Sources say a handful of Mann’s colleagues also were swept up in the layoff.

In addition, Nortel laid off Kevin McCarthy, global leader at Nortel’s UK-based Unified Communications Collaboration Centre, and his team of six or seven consultants.

McCarthy updated his LinkedIn profile on Monday to read, “Working on securing a new role with a new employer.”

It is unclear just how many employees were made redundant, but sources say the moves appear to signal that Nortel is beginning to shut down its side of the Innovative Communications Alliance (ICA) it formed in 2006 with Microsoft.

A Nortel spokesman said the company had no comment.

ICA is a joint effort to develop, sell and roll out UC and VoIP technology to corporate customers. The partnership was set to expire next year.

Craig Schuman, director of business development and strategy for the unified communications group at Microsoft, said Wednesday that “both Microsoft and Nortel remain fully committed to delivering customers the best unified communications solutions available. We are not in the position to assess the impact to the ICA until we understand Nortel’s plans for its enterprise division.”

Nortel’s plan is to sell off that division, which includes the UC equipment that is a foundational element of ICA.

Nortel is in the process of liquidating its assets and hoping to restructure under Chapter 11. Nortel CEO Mike Zafirovski has said the enterprise business is on the block.

Canada’s Globe and Mail is reporting that Nortel is close to selling the division to Avaya for $500 million.

Nortel’s asset liquidation could subtract from the ICA partnership Nortel’s telecommunications products, including its IP-PBX platform; the Nortel engineers working with Microsoft on jointly developed products; and Nortel Global Services, the consulting arm that provides glue for ICA.