Table:
|  | 2019 Goodwill | 2018 Goodwill |
| --- | --- | --- |
|  | £m | £m |
| Steam Specialties | 113.0 | 119.3 |
| Electric Thermal Solutions | 244.7 | 183.0 |
| Watson-Marlow | 60.0 | 65.7 |
| Total goodwill | 417.7 | 368.0 |
Paragraphs:
15 Goodwill and other intangible assets continued
Impairment
In accordance with the requirements of IAS 36 (Impairment of Assets), goodwill is allocated to the Group’s cash-generating units, or groups of cash-generating units, that are expected to benefit from the synergies of the business combination that gave rise to the goodwill.
During 2019, we performed a review on the basis of identification of our individual CGUs. As a result of this review, we have consolidated a number of our current individual CGUs into groups of CGUs that represent the lowest level to which goodwill is monitored for internal management purposes, being each operating segment as disclosed in Note 3. As a result, we performed an impairment review at an operating segment CGU level, the breakdown of the goodwill value at 31st December across these is shown below:
In order to complete the transition to performing goodwill impairment reviews at an operating segment level, we also performed a goodwill impairment review as at 31st December 2019 under the historical CGU basis. The result of this impairment review led to an impairment of £4.2m being recognised in respect of Watson-Marlow FlowSmart. No other impairment was recognised.
The goodwill balance has been tested for annual impairment on the following basis:
• the carrying values of goodwill have been assessed by reference to value in use. These have been estimated using cash flows based on forecast information for the next financial year which have been approved by the Board and then extended up to a further 9 years based on the most recent forecasts prepared by management; • pre-tax discount rates range from 11-12% (2018: 10-15%); • short to medium-term growth rates vary between 3-8% depending on detailed forecasts (2018: 2-8%). The range in rates excludes the annualised impact of owning Thermocoax for a first full year in 2020. The short to medium-term is defined as not more than 10 years; and • long-term growth rates are set using IMF forecasts and vary between 1.8-2.5% (2018: 0.8-3.0%).
Question:
How are the carrying values of goodwill estimated?
Answer: using cash flows based on forecast information for the next financial year which have been approved by the Board and then extended up to a further 9 years based on the most recent forecasts prepared by management