The Resident Labour Market Test has now been abolished and so advertising to show a shortage of suitable resident workers is no longer required in all cases.  Previously, under the Tier 2 General visa category you had to complete the Resident Labour Market Test in many cases.  This was for many employers a time consuming process; you had to advertise the vacancy, deal with job applicants and explain why the applicants were not suitable. However, even if not strictly necessary, it may be worth advertising the vacancy anyway to show the need to sponsor an overseas worker under the Skilled Worker visa scheme.