Exhibit
12(a) s302







CERTIFICATION OF ROLAND DIGGELMANN



302 CERTIFICATION



I, Roland Diggelmann, certify
that:



| | 1. | I have reviewed this annual
report on Form 20-F/A of Smith & Nephew plc;
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| | 2. | Based on my knowledge,
this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements
made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by
this report;
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| | 3. | Based on my knowledge,
the financial statements, and other financial information included in this report, fairly present in all material respects the
financial condition, results of operations and cash flows of the company as of, and for, the periods presented in this report;
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| | 4. | The company’s other
certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in
Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f)
and 15d-15(f)) for the company and have:
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| | a) | Designed such disclosure
controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that
material information relating to the company, including its consolidated subsidiaries, is made known to us by others within those
entities, particularly during the period in which this report is being prepared;
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| | b) | Designed such internal
control over financial reporting or caused such internal control over financial reporting to be designed under our supervision,
to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for
external purposes in accordance with generally accepted accounting principles;
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| | c) | Evaluated the effectiveness
of the company’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness
of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and
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| | d) | Disclosed in this report
any change in the company’s internal control over financial reporting that occurred during the period covered by the annual
report that has materially affected, or is reasonably likely to materially affect, the company’s internal control over financial
reporting; and
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| | 5. | The company’s other
certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting,
to the company’s auditors and the audit committee of the company’s board of directors (or persons performing the equivalent
functions):
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| | a) | All significant deficiencies
and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to
adversely affect the company’s ability to record, process, summarize and report financial information; and
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| | b) | Any fraud, whether or
not material, that involves management or other employees who have a significant role in the company’s internal control
over financial reporting.
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Date:
September 25, 2020



| | By:    | /s/ Roland Diggelmann   | 
| | ------ | ----------------------- | 
| | Name:  | Mr Roland Diggelmann    | 
| | Title: | Chief Executive Officer |